WIP endpoint abstractions + pruning integration / pruner rewrite

2024-11-24 09:24:09 +01:00 · 2020-05-29 00:09:43 +02:00 · 2020-05-29 00:09:43 +02:00 · 4a0104a44f
commit 4a0104a44f
parent f0146d03d3
26 changed files with 1672 additions and 164 deletions
--- a/config/config.go
+++ b/config/config.go
@ -309,6 +309,11 @@ type PruneKeepNotReplicated struct {
 	KeepSnapshotAtCursor bool   `yaml:"keep_snapshot_at_cursor,optional,default=true"`
 }

+type PruneKeepStepHolds struct {
+	Type             string   `yaml:"type"`
+	AdditionalJobIds []string `yaml:"additional_job_ids,optional"`
+}
+
 type PruneKeepLastN struct {
 	Type  string `yaml:"type"`
 	Count int    `yaml:"count"`
@ -480,6 +485,7 @@ func (t *ServeEnum) UnmarshalYAML(u func(interface{}, bool) error) (err error) {

 func (t *PruningEnum) UnmarshalYAML(u func(interface{}, bool) error) (err error) {
 	t.Ret, err = enumUnmarshal(u, map[string]interface{}{
+		"step_holds":     &PruneKeepStepHolds{},
 		"not_replicated": &PruneKeepNotReplicated{},
 		"last_n":         &PruneKeepLastN{},
 		"grid":           &PruneGrid{},
--- a/daemon/pruner.v2/fsstate_enumer.go
+++ b/daemon/pruner.v2/fsstate_enumer.go
@ -0,0 +1,72 @@
+// Code generated by "enumer -type=FSState -json"; DO NOT EDIT.
+
+//
+package pruner
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+const _FSStateName = "FSStateInitializedFSStatePlanningFSStatePlanErrFSStateExecutingFSStateExecuteErrFSStateExecuteSuccess"
+
+var _FSStateIndex = [...]uint8{0, 18, 33, 47, 63, 80, 101}
+
+func (i FSState) String() string {
+	if i < 0 || i >= FSState(len(_FSStateIndex)-1) {
+		return fmt.Sprintf("FSState(%d)", i)
+	}
+	return _FSStateName[_FSStateIndex[i]:_FSStateIndex[i+1]]
+}
+
+var _FSStateValues = []FSState{0, 1, 2, 3, 4, 5}
+
+var _FSStateNameToValueMap = map[string]FSState{
+	_FSStateName[0:18]:   0,
+	_FSStateName[18:33]:  1,
+	_FSStateName[33:47]:  2,
+	_FSStateName[47:63]:  3,
+	_FSStateName[63:80]:  4,
+	_FSStateName[80:101]: 5,
+}
+
+// FSStateString retrieves an enum value from the enum constants string name.
+// Throws an error if the param is not part of the enum.
+func FSStateString(s string) (FSState, error) {
+	if val, ok := _FSStateNameToValueMap[s]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to FSState values", s)
+}
+
+// FSStateValues returns all values of the enum
+func FSStateValues() []FSState {
+	return _FSStateValues
+}
+
+// IsAFSState returns "true" if the value is listed in the enum definition. "false" otherwise
+func (i FSState) IsAFSState() bool {
+	for _, v := range _FSStateValues {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}
+
+// MarshalJSON implements the json.Marshaler interface for FSState
+func (i FSState) MarshalJSON() ([]byte, error) {
+	return json.Marshal(i.String())
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface for FSState
+func (i *FSState) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return fmt.Errorf("FSState should be a string, got %s", data)
+	}
+
+	var err error
+	*i, err = FSStateString(s)
+	return err
+}
--- a/daemon/pruner.v2/pruner.go
+++ b/daemon/pruner.v2/pruner.go
@ -0,0 +1,454 @@
+package pruner
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/pkg/errors"
+	"github.com/zrepl/zrepl/daemon/logging"
+	"github.com/zrepl/zrepl/daemon/logging/trace"
+	"github.com/zrepl/zrepl/endpoint"
+	"github.com/zrepl/zrepl/pruning"
+	"github.com/zrepl/zrepl/zfs"
+)
+
+type Pruner struct {
+	fsfilter  endpoint.FSFilter
+	jid       endpoint.JobID
+	side      Side
+	keepRules []pruning.KeepRule
+
+	// all channels consumed by the run loop
+	reportReqs chan reportRequest
+	stopReqs   chan stopRequest
+	done       chan struct{}
+	fsListRes  chan fsListRes
+
+	state State
+
+	listFilesystemsError error       // only in state StateListFilesystemsError
+	fsPruners            []*FSPruner // only in state StateFanOutFilesystems
+}
+
+//go:generate enumer -type=State -json
+type State int
+
+const (
+	StateInitialized State = iota
+	StateListFilesystems
+	StateListFilesystemsError
+	StateFanOutFilesystems
+	StateDone
+)
+
+type Report struct {
+	State                State
+	ListFilesystemsError error       // only valid in StateListFilesystemsError
+	Filesystems          []*FSReport // valid from StateFanOutFilesystems
+}
+
+type reportRequest struct {
+	ctx   context.Context
+	reply chan *Report
+}
+
+type runRequest struct {
+	complete chan struct{}
+}
+
+type stopRequest struct {
+	complete chan struct{}
+}
+
+type fsListRes struct {
+	filesystems []*zfs.DatasetPath
+	err         error
+}
+
+type Side interface {
+	// may return both nil, indicating there is no replication position
+	GetReplicationPosition(ctx context.Context, fs string) (*zfs.FilesystemVersion, error)
+	isSide() Side
+}
+
+func NewPruner(fsfilter endpoint.FSFilter, jid endpoint.JobID, side Side, keepRules []pruning.KeepRule) *Pruner {
+	return &Pruner{
+		fsfilter,
+		jid,
+		side,
+		keepRules,
+		make(chan reportRequest),
+		make(chan stopRequest),
+		make(chan struct{}),
+		make(chan fsListRes),
+		StateInitialized,
+		nil,
+		nil,
+	}
+}
+
+func (p *Pruner) Run(ctx context.Context) *Report {
+
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	if p.state != StateInitialized {
+		panic("Run can onl[y be called once")
+	}
+
+	go func() {
+		fss, err := zfs.ZFSListMapping(ctx, p.fsfilter)
+		p.fsListRes <- fsListRes{fss, err}
+	}()
+
+	for {
+		select {
+		case res := <-p.fsListRes:
+			if res.err != nil {
+				p.state = StateListFilesystemsError
+				p.listFilesystemsError = res.err
+				close(p.done)
+				continue
+			}
+
+			p.state = StateFanOutFilesystems
+
+			p.fsPruners = make([]*FSPruner, len(res.filesystems))
+			_, add, end := trace.WithTaskGroup(ctx, "pruner-fan-out-fs")
+			for i, fs := range res.filesystems {
+				p.fsPruners[i] = NewFSPruner(p.jid, p.side, p.keepRules, fs)
+				add(func(ctx context.Context) {
+					p.fsPruners[i].Run(ctx)
+				})
+			}
+			go func() {
+				end()
+				close(p.done)
+			}()
+
+		case req := <-p.stopReqs:
+			cancel()
+			go func() {
+				<-p.done
+				close(req.complete)
+			}()
+		case req := <-p.reportReqs:
+			req.reply <- p.report(req.ctx)
+		case <-p.done:
+			p.state = StateDone
+			return p.report(ctx)
+		}
+	}
+}
+
+func (p *Pruner) Report(ctx context.Context) *Report {
+	req := reportRequest{
+		ctx:   ctx,
+		reply: make(chan *Report, 1),
+	}
+	select {
+	case p.reportReqs <- req:
+		return <-req.reply
+	case <-ctx.Done():
+		return nil
+	case <-p.done:
+		return nil
+	}
+}
+
+func (p *Pruner) report(ctx context.Context) *Report {
+	fsreports := make([]*FSReport, len(p.fsPruners))
+	for i := range fsreports {
+		fsreports[i] = p.fsPruners[i].report()
+	}
+	return &Report{
+		State:                p.state,
+		ListFilesystemsError: p.listFilesystemsError,
+		Filesystems:          fsreports,
+	}
+}
+
+// implements pruning.Snapshot
+type snapshot struct {
+	replicated bool
+	stepHolds  []pruning.StepHold
+	zfs.FilesystemVersion
+
+	state     SnapState
+	destroyOp *zfs.DestroySnapOp
+}
+
+//go:generate enumer -type=SnapState -json
+type SnapState int
+
+const (
+	SnapStateInitialized SnapState = iota
+	SnapStateKeeping
+	SnapStateDeletePending
+	SnapStateDeleteAttempted
+)
+
+// implements pruning.StepHold
+type stepHold struct {
+	endpoint.Abstraction
+}
+
+func (s snapshot) Replicated() bool              { return s.replicated }
+func (s snapshot) StepHolds() []pruning.StepHold { return s.stepHolds }
+
+func (s stepHold) GetJobID() endpoint.JobID { return *s.Abstraction.GetJobID() }
+
+type FSPruner struct {
+	jid       endpoint.JobID
+	side      Side
+	keepRules []pruning.KeepRule
+	fsp       *zfs.DatasetPath
+
+	state FSState
+
+	// all channels consumed by the run loop
+	planned    chan fsPlanRes
+	executed   chan fsExecuteRes
+	done       chan struct{}
+	reportReqs chan fsReportReq
+
+	keepList    []*snapshot // valid in FSStateExecuting and forward
+	destroyList []*snapshot // valid in FSStateExecuting and forward, field .destroyOp is invalid until FSStateExecuting is left
+
+}
+
+type fsPlanRes struct {
+	keepList    []*snapshot
+	destroyList []*snapshot
+	err         error
+}
+
+type fsExecuteRes struct {
+	completedDestroyOps []*zfs.DestroySnapOp // same len() as FSPruner.destroyList
+}
+
+type fsReportReq struct {
+	res chan *FSReport
+}
+
+type FSReport struct {
+	State    FSState
+	KeepList []*SnapReport
+	Destroy  []*SnapReport
+}
+
+type SnapReport struct {
+	State         SnapState
+	Name          string
+	Replicated    bool
+	StepHoldCount int
+	DestroyError  error
+}
+
+//go:generate enumer -type=FSState -json
+type FSState int
+
+const (
+	FSStateInitialized FSState = iota
+	FSStatePlanning
+	FSStatePlanErr
+	FSStateExecuting
+	FSStateExecuteErr
+	FSStateExecuteSuccess
+)
+
+func (s FSState) IsTerminal() bool {
+	return s == FSStatePlanErr || s == FSStateExecuteErr || s == FSStateExecuteSuccess
+}
+
+func NewFSPruner(jid endpoint.JobID, side Side, keepRules []pruning.KeepRule, fsp *zfs.DatasetPath) *FSPruner {
+	return &FSPruner{
+		jid, side, keepRules, fsp,
+		FSStateInitialized,
+		make(chan fsPlanRes),
+		make(chan fsExecuteRes),
+		make(chan struct{}),
+		make(chan fsReportReq),
+		nil, nil,
+	}
+}
+
+func (p *FSPruner) Run(ctx context.Context) *FSReport {
+
+	defer func() {
+	}()
+
+	p.state = FSStatePlanning
+
+	go func() { p.planned <- p.plan(ctx) }()
+
+out:
+	for !p.state.IsTerminal() {
+		select {
+		case res := <-p.planned:
+
+			if res.err != nil {
+				p.state = FSStatePlanErr
+				continue
+			}
+			p.state = FSStateExecuting
+			p.keepList = res.keepList
+			p.destroyList = res.destroyList
+
+			go func() { p.executed <- p.execute(ctx, p.destroyList) }()
+
+		case res := <-p.executed:
+
+			if len(res.completedDestroyOps) != len(p.destroyList) {
+				panic("impl error: completedDestroyOps is a vector corresponding to entries in p.destroyList")
+			}
+
+			var erronous []*zfs.DestroySnapOp
+			for i, op := range res.completedDestroyOps {
+				if *op.ErrOut != nil {
+					erronous = append(erronous, op)
+				}
+				p.destroyList[i].destroyOp = op
+				p.destroyList[i].state = SnapStateDeleteAttempted
+			}
+			if len(erronous) > 0 {
+				p.state = FSStateExecuteErr
+			} else {
+				p.state = FSStateExecuteSuccess
+			}
+
+			close(p.done)
+
+		case <-p.reportReqs:
+			panic("unimp")
+		case <-p.done:
+			break out
+		}
+	}
+
+	// TODO render last FS report
+	return nil
+}
+
+func (p *FSPruner) plan(ctx context.Context) fsPlanRes {
+	fs := p.fsp.ToString()
+	vs, err := zfs.ZFSListFilesystemVersions(ctx, p.fsp, zfs.ListFilesystemVersionsOptions{})
+	if err != nil {
+		return fsPlanRes{err: errors.Wrap(err, "list filesystem versions")}
+	}
+
+	allJobsStepHolds, absErrs, err := endpoint.ListAbstractions(ctx, endpoint.ListZFSHoldsAndBookmarksQuery{
+		FS: endpoint.ListZFSHoldsAndBookmarksQueryFilesystemFilter{
+			FS: &fs,
+		},
+		What: endpoint.AbstractionTypeSet{
+			endpoint.AbstractionStepHold: true,
+		},
+		Concurrency: 1,
+	})
+	if err != nil {
+		return fsPlanRes{err: errors.Wrap(err, "list abstractions")}
+	}
+	if len(absErrs) > 0 {
+		logging.GetLogger(ctx, logging.SubsysPruning).WithError(endpoint.ListAbstractionsErrors(absErrs)).
+			Error("error listing some step holds, prune attempt might fail with 'dataset is busy' errors")
+	}
+
+	repPos, err := p.side.GetReplicationPosition(ctx, p.fsp.ToString())
+	if err != nil {
+		return fsPlanRes{err: errors.Wrap(err, "get replication position")}
+	}
+
+	vsAsSnaps := make([]pruning.Snapshot, len(vs))
+	for i := range vs {
+		var repPosCreateTxgOrZero uint64
+		if repPos != nil {
+			repPosCreateTxgOrZero = repPos.GetCreateTXG()
+		}
+		s := &snapshot{
+			state:             SnapStateInitialized,
+			FilesystemVersion: vs[i],
+			replicated:        vs[i].GetCreateTXG() <= repPosCreateTxgOrZero,
+		}
+		for _, h := range allJobsStepHolds {
+			if zfs.FilesystemVersionEqualIdentity(vs[i], h.GetFilesystemVersion()) {
+				s.stepHolds = append(s.stepHolds, stepHold{h})
+			}
+		}
+		vsAsSnaps[i] = s
+	}
+
+	downcastToSnapshots := func(l []pruning.Snapshot) (r []*snapshot) {
+		r = make([]*snapshot, len(l))
+		for i, e := range l {
+			r[i] = e.(*snapshot)
+		}
+		return r
+	}
+	pruningResult := pruning.PruneSnapshots(vsAsSnaps, p.keepRules)
+	remove, keep := downcastToSnapshots(pruningResult.Remove), downcastToSnapshots(pruningResult.Keep)
+	if len(remove)+len(keep) != len(vsAsSnaps) {
+		for _, s := range vsAsSnaps {
+			r, _ := json.MarshalIndent(s.(*snapshot).report(), "", "  ")
+			fmt.Fprintf(os.Stderr, "%s\n", string(r))
+		}
+		panic("indecisive")
+	}
+
+	for _, s := range remove {
+		s.state = SnapStateDeletePending
+	}
+	for _, s := range keep {
+		s.state = SnapStateKeeping
+	}
+
+	return fsPlanRes{keepList: keep, destroyList: remove, err: nil}
+}
+
+func (p *FSPruner) execute(ctx context.Context, destroyList []*snapshot) fsExecuteRes {
+	ops := make([]*zfs.DestroySnapOp, len(destroyList))
+	for i, fsv := range p.destroyList {
+		ops[i] = &zfs.DestroySnapOp{
+			Filesystem: p.fsp.ToString(),
+			Name:       fsv.GetName(),
+			ErrOut:     new(error),
+		}
+	}
+	zfs.ZFSDestroyFilesystemVersions(ctx, ops)
+
+	return fsExecuteRes{completedDestroyOps: ops}
+}
+
+func (p *FSPruner) report() *FSReport {
+	return &FSReport{
+		State:    p.state,
+		KeepList: p.reportRenderSnapReports(p.keepList),
+		Destroy:  p.reportRenderSnapReports(p.destroyList),
+	}
+}
+
+func (p *FSPruner) reportRenderSnapReports(l []*snapshot) (r []*SnapReport) {
+	r = make([]*SnapReport, len(l))
+	for i := range l {
+		r[i] = l[i].report()
+	}
+	return r
+}
+
+func (s *snapshot) report() *SnapReport {
+	var snapErr error
+	if s.state == SnapStateDeleteAttempted {
+		if *s.destroyOp.ErrOut != nil {
+			snapErr = (*s.destroyOp.ErrOut)
+		}
+	}
+	return &SnapReport{
+		State:         s.state,
+		Name:          s.Name,
+		Replicated:    s.Replicated(),
+		StepHoldCount: len(s.stepHolds),
+		DestroyError:  snapErr,
+	}
+}
--- a/daemon/pruner.v2/pruner_side.go
+++ b/daemon/pruner.v2/pruner_side.go
@ -0,0 +1,27 @@
+package pruner
+
+import (
+	"context"
+
+	"github.com/zrepl/zrepl/endpoint"
+	"github.com/zrepl/zrepl/zfs"
+)
+
+type SideSender struct {
+	jobID endpoint.JobID
+}
+
+func NewSideSender(jid endpoint.JobID) *SideSender {
+	return &SideSender{jid}
+}
+
+func (s *SideSender) isSide() Side { return nil }
+
+var _ Side = (*SideSender)(nil)
+
+func (s *SideSender) GetReplicationPosition(ctx context.Context, fs string) (*zfs.FilesystemVersion, error) {
+	if fs == "" {
+		panic("must not pass zero value for fs")
+	}
+	return endpoint.GetMostRecentReplicationCursorOfJob(ctx, fs, s.jobID)
+}
--- a/daemon/pruner.v2/snapstate_enumer.go
+++ b/daemon/pruner.v2/snapstate_enumer.go
@ -0,0 +1,70 @@
+// Code generated by "enumer -type=SnapState -json"; DO NOT EDIT.
+
+//
+package pruner
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+const _SnapStateName = "SnapStateInitializedSnapStateKeepingSnapStateDeletePendingSnapStateDeleteAttempted"
+
+var _SnapStateIndex = [...]uint8{0, 20, 36, 58, 82}
+
+func (i SnapState) String() string {
+	if i < 0 || i >= SnapState(len(_SnapStateIndex)-1) {
+		return fmt.Sprintf("SnapState(%d)", i)
+	}
+	return _SnapStateName[_SnapStateIndex[i]:_SnapStateIndex[i+1]]
+}
+
+var _SnapStateValues = []SnapState{0, 1, 2, 3}
+
+var _SnapStateNameToValueMap = map[string]SnapState{
+	_SnapStateName[0:20]:  0,
+	_SnapStateName[20:36]: 1,
+	_SnapStateName[36:58]: 2,
+	_SnapStateName[58:82]: 3,
+}
+
+// SnapStateString retrieves an enum value from the enum constants string name.
+// Throws an error if the param is not part of the enum.
+func SnapStateString(s string) (SnapState, error) {
+	if val, ok := _SnapStateNameToValueMap[s]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to SnapState values", s)
+}
+
+// SnapStateValues returns all values of the enum
+func SnapStateValues() []SnapState {
+	return _SnapStateValues
+}
+
+// IsASnapState returns "true" if the value is listed in the enum definition. "false" otherwise
+func (i SnapState) IsASnapState() bool {
+	for _, v := range _SnapStateValues {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}
+
+// MarshalJSON implements the json.Marshaler interface for SnapState
+func (i SnapState) MarshalJSON() ([]byte, error) {
+	return json.Marshal(i.String())
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface for SnapState
+func (i *SnapState) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return fmt.Errorf("SnapState should be a string, got %s", data)
+	}
+
+	var err error
+	*i, err = SnapStateString(s)
+	return err
+}
--- a/daemon/pruner.v2/state_enumer.go
+++ b/daemon/pruner.v2/state_enumer.go
@ -0,0 +1,71 @@
+// Code generated by "enumer -type=State -json"; DO NOT EDIT.
+
+//
+package pruner
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+const _StateName = "StateInitializedStateListFilesystemsStateListFilesystemsErrorStateFanOutFilesystemsStateDone"
+
+var _StateIndex = [...]uint8{0, 16, 36, 61, 83, 92}
+
+func (i State) String() string {
+	if i < 0 || i >= State(len(_StateIndex)-1) {
+		return fmt.Sprintf("State(%d)", i)
+	}
+	return _StateName[_StateIndex[i]:_StateIndex[i+1]]
+}
+
+var _StateValues = []State{0, 1, 2, 3, 4}
+
+var _StateNameToValueMap = map[string]State{
+	_StateName[0:16]:  0,
+	_StateName[16:36]: 1,
+	_StateName[36:61]: 2,
+	_StateName[61:83]: 3,
+	_StateName[83:92]: 4,
+}
+
+// StateString retrieves an enum value from the enum constants string name.
+// Throws an error if the param is not part of the enum.
+func StateString(s string) (State, error) {
+	if val, ok := _StateNameToValueMap[s]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to State values", s)
+}
+
+// StateValues returns all values of the enum
+func StateValues() []State {
+	return _StateValues
+}
+
+// IsAState returns "true" if the value is listed in the enum definition. "false" otherwise
+func (i State) IsAState() bool {
+	for _, v := range _StateValues {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}
+
+// MarshalJSON implements the json.Marshaler interface for State
+func (i State) MarshalJSON() ([]byte, error) {
+	return json.Marshal(i.String())
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface for State
+func (i *State) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return fmt.Errorf("State should be a string, got %s", data)
+	}
+
+	var err error
+	*i, err = StateString(s)
+	return err
+}
--- a/daemon/pruner/pruner.go
+++ b/daemon/pruner/pruner.go
@ -20,15 +20,14 @@ import (
 )

 // Try to keep it compatible with github.com/zrepl/zrepl/endpoint.Endpoint
-type History interface {
-	ReplicationCursor(ctx context.Context, req *pdu.ReplicationCursorReq) (*pdu.ReplicationCursorRes, error)
+type Endpoint interface {
 	ListFilesystems(ctx context.Context, req *pdu.ListFilesystemReq) (*pdu.ListFilesystemRes, error)
+	ListFilesystemVersions(ctx context.Context, req *pdu.ListFilesystemVersionsReq) (*pdu.ListFilesystemVersionsRes, error)
 }

 // Try to keep it compatible with github.com/zrepl/zrepl/endpoint.Endpoint
 type Target interface {
-	ListFilesystems(ctx context.Context, req *pdu.ListFilesystemReq) (*pdu.ListFilesystemRes, error)
-	ListFilesystemVersions(ctx context.Context, req *pdu.ListFilesystemVersionsReq) (*pdu.ListFilesystemVersionsRes, error)
+	Endpoint
 	DestroySnapshots(ctx context.Context, req *pdu.DestroySnapshotsReq) (*pdu.DestroySnapshotsRes, error)
 }

@ -46,13 +45,14 @@ func GetLogger(ctx context.Context) Logger {
 }

 type args struct {
-	ctx                            context.Context
-	target                         Target
-	receiver                       History
-	rules                          []pruning.KeepRule
-	retryWait                      time.Duration
-	considerSnapAtCursorReplicated bool
-	promPruneSecs                  prometheus.Observer
+	ctx                              context.Context
+	target                           Target
+	sender, receiver                 Endpoint
+	rules                            []pruning.KeepRule
+	retryWait                        time.Duration
+	considerSnapAtCursorReplicated   bool
+	convertAnyStepHoldToStepBookmark bool
+	promPruneSecs                    prometheus.Observer
 }

 type Pruner struct {
@ -70,11 +70,12 @@ type Pruner struct {
 }

 type PrunerFactory struct {
-	senderRules                    []pruning.KeepRule
-	receiverRules                  []pruning.KeepRule
-	retryWait                      time.Duration
-	considerSnapAtCursorReplicated bool
-	promPruneSecs                  *prometheus.HistogramVec
+	senderRules                      []pruning.KeepRule
+	receiverRules                    []pruning.KeepRule
+	retryWait                        time.Duration
+	considerSnapAtCursorReplicated   bool
+	convertAnyStepHoldToStepBookmark bool
+	promPruneSecs                    *prometheus.HistogramVec
 }

 type LocalPrunerFactory struct {
@ -122,25 +123,35 @@ func NewPrunerFactory(in config.PruningSenderReceiver, promPruneSecs *prometheus
 		}
 		considerSnapAtCursorReplicated = considerSnapAtCursorReplicated || !knr.KeepSnapshotAtCursor
 	}
+
+	convertAnyStepHoldToStepBookmark := false
+	for _, r := range in.KeepSender {
+		_, ok := r.Ret.(*config.PruneKeepStepHolds)
+		convertAnyStepHoldToStepBookmark = convertAnyStepHoldToStepBookmark || ok
+	}
+
 	f := &PrunerFactory{
-		senderRules:                    keepRulesSender,
-		receiverRules:                  keepRulesReceiver,
-		retryWait:                      envconst.Duration("ZREPL_PRUNER_RETRY_INTERVAL", 10*time.Second),
-		considerSnapAtCursorReplicated: considerSnapAtCursorReplicated,
-		promPruneSecs:                  promPruneSecs,
+		senderRules:                      keepRulesSender,
+		receiverRules:                    keepRulesReceiver,
+		retryWait:                        envconst.Duration("ZREPL_PRUNER_RETRY_INTERVAL", 10*time.Second),
+		considerSnapAtCursorReplicated:   considerSnapAtCursorReplicated,
+		convertAnyStepHoldToStepBookmark: convertAnyStepHoldToStepBookmark,
+		promPruneSecs:                    promPruneSecs,
 	}
 	return f, nil
 }

-func (f *PrunerFactory) BuildSenderPruner(ctx context.Context, target Target, receiver History) *Pruner {
+func (f *PrunerFactory) BuildSenderPruner(ctx context.Context, sender Target, receiver Endpoint) *Pruner {
 	p := &Pruner{
 		args: args{
 			context.WithValue(ctx, contextKeyPruneSide, "sender"),
-			target,
+			sender,
+			sender,
 			receiver,
 			f.senderRules,
 			f.retryWait,
 			f.considerSnapAtCursorReplicated,
+			f.convertAnyStepHoldToStepBookmark,
 			f.promPruneSecs.WithLabelValues("sender"),
 		},
 		state: Plan,
@ -148,15 +159,17 @@ func (f *PrunerFactory) BuildSenderPruner(ctx context.Context, target Target, re
 	return p
 }

-func (f *PrunerFactory) BuildReceiverPruner(ctx context.Context, target Target, receiver History) *Pruner {
+func (f *PrunerFactory) BuildReceiverPruner(ctx context.Context, receiver Target, sender Endpoint) *Pruner {
 	p := &Pruner{
 		args: args{
 			context.WithValue(ctx, contextKeyPruneSide, "receiver"),
-			target,
+			receiver,
+			sender,
 			receiver,
 			f.receiverRules,
 			f.retryWait,
 			false, // senseless here anyways
+			false, // senseless here anyways
 			f.promPruneSecs.WithLabelValues("receiver"),
 		},
 		state: Plan,
@ -164,15 +177,17 @@ func (f *PrunerFactory) BuildReceiverPruner(ctx context.Context, target Target,
 	return p
 }

-func (f *LocalPrunerFactory) BuildLocalPruner(ctx context.Context, target Target, receiver History) *Pruner {
+func (f *LocalPrunerFactory) BuildLocalPruner(ctx context.Context, target Target) *Pruner {
 	p := &Pruner{
 		args: args{
 			context.WithValue(ctx, contextKeyPruneSide, "local"),
 			target,
-			receiver,
+			target,
+			target,
 			f.keepRules,
 			f.retryWait,
 			false, // considerSnapAtCursorReplicated is not relevant for local pruning
+			false, // convertAnyStepHoldToStepBookmark is not relevant for local pruning
 			f.promPruneSecs.WithLabelValues("local"),
 		},
 		state: Plan,
@ -341,11 +356,13 @@ func (s snapshot) Replicated() bool { return s.replicated }

 func (s snapshot) Date() time.Time { return s.date }

+func (s snapshot) CreateTXG() uint64 { return s.fsv.GetCreateTXG() }
+
 func doOneAttempt(a *args, u updater) {

-	ctx, target, receiver := a.ctx, a.target, a.receiver
+	ctx, sender, receiver, target := a.ctx, a.sender, a.receiver, a.target

-	sfssres, err := receiver.ListFilesystems(ctx, &pdu.ListFilesystemReq{})
+	sfssres, err := sender.ListFilesystems(ctx, &pdu.ListFilesystemReq{})
 	if err != nil {
 		u(func(p *Pruner) {
 			p.state = PlanErr
@ -407,6 +424,10 @@ tfss_loop:

 		pfs.snaps = make([]pruning.Snapshot, 0, len(tfsvs))

+		receiver.ListFilesystemVersions(ctx, &pdu.ListFilesystemVersionsReq{
+			Filesystem: tfs.Path,
+		})
+
 		rcReq := &pdu.ReplicationCursorReq{
 			Filesystem: tfs.Path,
 		}
@ -415,6 +436,7 @@ tfss_loop:
 			pfsPlanErrAndLog(err, "cannot get replication cursor bookmark")
 			continue tfss_loop
 		}
+
 		if rc.GetNotexist() {
 			err := errors.New("replication cursor bookmark does not exist (one successful replication is required before pruning works)")
 			pfsPlanErrAndLog(err, "")
--- a/endpoint/endpoint.go
+++ b/endpoint/endpoint.go
@ -112,6 +112,13 @@ func (s *Sender) ListFilesystemVersions(ctx context.Context, r *pdu.ListFilesyst
 	for i := range fsvs {
 		rfsvs[i] = pdu.FilesystemVersionFromZFS(&fsvs[i])
 	}
+
+	sendAbstractions := sendAbstractionsCacheSingleton.GetByFS(ctx, lp.ToString())
+	rSabsInfo := make([]*pdu.SendAbstraction, len(sendAbstractions))
+	for i := range rSabsInfo {
+		rSabsInfo[i] = SendAbstractionToPDU(sendAbstractions[i])
+	}
+
 	res := &pdu.ListFilesystemVersionsRes{Versions: rfsvs}
 	return res, nil

--- a/endpoint/endpoint_send_abstractions_cache.go
+++ b/endpoint/endpoint_send_abstractions_cache.go
@ -82,6 +82,24 @@ func (s *sendAbstractionsCache) InvalidateFSCache(fs string) {

 }

+func (s *sendAbstractionsCache) GetByFS(ctx context.Context, fs string) (ret []Abstraction) {
+	defer s.mtx.Lock().Unlock()
+	defer trace.WithSpanFromStackUpdateCtx(&ctx)()
+	if fs == "" {
+		panic("must not pass zero-value fs")
+	}
+
+	s.tryLoadOnDiskSendAbstractions(ctx, fs)
+
+	for _, a := range s.abstractions {
+		if a.GetFS() == fs {
+			ret = append(ret, a)
+		}
+	}
+
+	return ret
+}
+
 // - logs errors in getting on-disk abstractions
 // - only fetches on-disk abstractions once, but every time from the in-memory store
 //
--- a/endpoint/endpoint_zfs_abstraction_pdu.go
+++ b/endpoint/endpoint_zfs_abstraction_pdu.go
@ -0,0 +1,28 @@
+package endpoint
+
+import "github.com/zrepl/zrepl/replication/logic/pdu"
+
+func SendAbstractionToPDU(a Abstraction) *pdu.SendAbstraction {
+	var ty pdu.SendAbstraction_SendAbstractionType
+	switch a.GetType() {
+	case AbstractionLastReceivedHold:
+		panic(a)
+	case AbstractionReplicationCursorBookmarkV1:
+		panic(a)
+	case AbstractionReplicationCursorBookmarkV2:
+		ty = pdu.SendAbstraction_ReplicationCursorV2
+	case AbstractionStepHold:
+		ty = pdu.SendAbstraction_StepHold
+	case AbstractionStepBookmark:
+		ty = pdu.SendAbstraction_StepBookmark
+	default:
+		panic(a)
+	}
+
+	version := a.GetFilesystemVersion()
+	return &pdu.SendAbstraction{
+		Type:    ty,
+		JobID:   (*a.GetJobID()).String(),
+		Version: pdu.FilesystemVersionFromZFS(&version),
+	}
+}
--- a/platformtest/tests/batchDestroy.go
+++ b/platformtest/tests/batchDestroy.go
@ -2,8 +2,9 @@ package tests

 import (
 	"fmt"
-	"strings"

+	"github.com/kr/pretty"
+	"github.com/stretchr/testify/require"
 	"github.com/zrepl/zrepl/platformtest"
 	"github.com/zrepl/zrepl/zfs"
 )
@ -17,7 +18,9 @@ func BatchDestroy(ctx *platformtest.Context) {
 		+  "foo bar@1"
 		+  "foo bar@2"
 		+  "foo bar@3"
+		+  "foo bar@4"
 		R  zfs hold zrepl_platformtest "${ROOTDS}/foo bar@2"
+		R  zfs hold zrepl_platformtest "${ROOTDS}/foo bar@4"
 	`)

 	reqs := []*zfs.DestroySnapOp{
@ -31,24 +34,40 @@ func BatchDestroy(ctx *platformtest.Context) {
 			Filesystem: fmt.Sprintf("%s/foo bar", ctx.RootDataset),
 			Name:       "2",
 		},
+		&zfs.DestroySnapOp{
+			ErrOut:     new(error),
+			Filesystem: fmt.Sprintf("%s/foo bar", ctx.RootDataset),
+			Name:       "non existent",
+		},
+		&zfs.DestroySnapOp{
+			ErrOut:     new(error),
+			Filesystem: fmt.Sprintf("%s/foo bar", ctx.RootDataset),
+			Name:       "4",
+		},
 	}
 	zfs.ZFSDestroyFilesystemVersions(ctx, reqs)
+
+	pretty.Println(reqs)
+
 	if *reqs[0].ErrOut != nil {
 		panic("expecting no error")
 	}
-	err := (*reqs[1].ErrOut).Error()
-	if !strings.Contains(err, fmt.Sprintf("%s/foo bar@2", ctx.RootDataset)) {
-		panic(fmt.Sprintf("expecting error about being unable to destroy @2: %T\n%s", err, err))
-	}
+
+	eBusy, ok := (*reqs[1].ErrOut).(*zfs.ErrDestroySnapshotDatasetIsBusy)
+	require.True(ctx, ok)
+	require.Equal(ctx, reqs[1].Name, eBusy.Name)
+
+	require.Nil(ctx, *reqs[2].ErrOut, "destroying non-existent snap is not an error (idempotence)")
+
+	eBusy, ok = (*reqs[3].ErrOut).(*zfs.ErrDestroySnapshotDatasetIsBusy)
+	require.True(ctx, ok)
+	require.Equal(ctx, reqs[3].Name, eBusy.Name)

 	platformtest.Run(ctx, platformtest.PanicErr, ctx.RootDataset, `
 	!N "foo bar@3"
 	!E "foo bar@1"
 	!E "foo bar@2"
-	R zfs release zrepl_platformtest "${ROOTDS}/foo bar@2"
-	-  "foo bar@2"
-	-  "foo bar@1"
-	-  "foo bar"
+	!E "foo bar@4"
 	`)

 }
--- a/platformtest/tests/generated_cases.go
+++ b/platformtest/tests/generated_cases.go
@ -14,6 +14,7 @@ var Cases = []Case{BatchDestroy,
 	ListFilesystemVersionsUserrefs,
 	ListFilesystemVersionsZeroExistIsNotAnError,
 	ListFilesystemsNoFilter,
+	Pruner2NotReplicated,
 	ReceiveForceIntoEncryptedErr,
 	ReceiveForceRollbackWorksUnencrypted,
 	ReplicationIncrementalCleansUpStaleAbstractionsWithCacheOnSecondReplication,
--- a/platformtest/tests/pruner.go.deact
+++ b/platformtest/tests/pruner.go.deact
@ -0,0 +1,331 @@
+package tests
+
+import (
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/require"
+	"github.com/zrepl/zrepl/config"
+	"github.com/zrepl/zrepl/daemon/filters"
+	"github.com/zrepl/zrepl/daemon/pruner"
+	"github.com/zrepl/zrepl/endpoint"
+	"github.com/zrepl/zrepl/platformtest"
+	"github.com/zrepl/zrepl/zfs"
+)
+
+func PrunerNotReplicated(ctx *platformtest.Context) {
+
+	platformtest.Run(ctx, platformtest.PanicErr, ctx.RootDataset, `
+        DESTROYROOT
+        CREATEROOT
+        +  "foo bar"
+        +  "foo bar@1"
+        +  "foo bar@2"
+        +  "foo bar@3"
+        +  "foo bar@4"
+        +  "foo bar@5"
+    `)
+
+	c, err := config.ParseConfigBytes([]byte(fmt.Sprintf(`
+jobs:
+- name: prunetest
+  type: push
+  filesystems: {
+      "%s/foo bar<": true
+  }
+  connect:
+    type: tcp
+    address: 255.255.255.255:255
+  snapshotting:
+    type: manual
+  pruning:
+    keep_sender:
+    - type: not_replicated
+    - type: last_n
+      count: 1
+    keep_receiver:
+    - type: last_n
+      count: 2
+    `, ctx.RootDataset)))
+	require.NoError(ctx, err)
+
+	pushJob := c.Jobs[0].Ret.(*config.PushJob)
+
+	dummyHistVec := prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "foo",
+		Subsystem: "foo",
+		Name:      "foo",
+		Help:      "foo",
+	}, []string{"foo"})
+
+	prunerFactory, err := pruner.NewPrunerFactory(pushJob.Pruning, dummyHistVec)
+	require.NoError(ctx, err)
+
+	senderJid := endpoint.MustMakeJobID("sender-job")
+
+	fsfilter, err := filters.DatasetMapFilterFromConfig(pushJob.Filesystems)
+	require.NoError(ctx, err)
+
+	sender := endpoint.NewSender(endpoint.SenderConfig{
+		FSF: fsfilter,
+		Encrypt: &zfs.NilBool{
+			B: false,
+		},
+		JobID: senderJid,
+	})
+
+	fs := ctx.RootDataset + "/foo bar"
+
+	// create a replication cursor to make pruning work at all
+	_, err = endpoint.CreateReplicationCursor(ctx, fs, fsversion(ctx, fs, "@2"), senderJid)
+	require.NoError(ctx, err)
+
+	p := prunerFactory.BuildSenderPruner(ctx, sender, sender)
+
+	p.Prune()
+
+	report := p.Report()
+
+	reportJSON, err := json.MarshalIndent(report, "", "  ")
+	require.NoError(ctx, err)
+	ctx.Logf("%s\n", string(reportJSON))
+
+	require.Equal(ctx, pruner.Done.String(), report.State)
+	require.Len(ctx, report.Completed, 1)
+	fsReport := report.Completed[0]
+	require.Equal(ctx, fs, fsReport.Filesystem)
+	require.Empty(ctx, fsReport.SkipReason)
+	require.Empty(ctx, fsReport.LastError)
+	require.Len(ctx, fsReport.DestroyList, 1)
+	require.Equal(ctx, fsReport.DestroyList[0], pruner.SnapshotReport{
+		Name:       "1",
+		Replicated: true,
+		Date:       fsReport.DestroyList[0].Date,
+	})
+
+}
+
+func PrunerNoKeepNotReplicatedNoKeepStepHoldConvertsAnyStepHoldToBookmark(ctx *platformtest.Context) {
+
+	platformtest.Run(ctx, platformtest.PanicErr, ctx.RootDataset, `
+        DESTROYROOT
+        CREATEROOT
+        +  "foo bar"
+        +  "foo bar@1"
+        +  "foo bar@2"
+        +  "foo bar@3"
+        +  "foo bar@4"
+        +  "foo bar@5"
+    `)
+
+	c, err := config.ParseConfigBytes([]byte(fmt.Sprintf(`
+jobs:
+- name: prunetest
+  type: push
+  filesystems: {
+      "%s/foo bar<": true
+  }
+  connect:
+    type: tcp
+    address: 255.255.255.255:255
+  snapshotting:
+    type: manual
+  pruning:
+    keep_sender:
+    - type: last_n
+      count: 1
+    keep_receiver:
+    - type: last_n
+      count: 2
+    `, ctx.RootDataset)))
+	require.NoError(ctx, err)
+
+	pushJob := c.Jobs[0].Ret.(*config.PushJob)
+
+	dummyHistVec := prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "foo",
+		Subsystem: "foo",
+		Name:      "foo",
+		Help:      "foo",
+	}, []string{"foo"})
+
+	prunerFactory, err := pruner.NewPrunerFactory(pushJob.Pruning, dummyHistVec)
+	require.NoError(ctx, err)
+
+	senderJid := endpoint.MustMakeJobID("sender-job")
+
+	fsfilter, err := filters.DatasetMapFilterFromConfig(pushJob.Filesystems)
+	require.NoError(ctx, err)
+
+	sender := endpoint.NewSender(endpoint.SenderConfig{
+		FSF: fsfilter,
+		Encrypt: &zfs.NilBool{
+			B: false,
+		},
+        JobID: senderJid,
+	})
+
+	fs := ctx.RootDataset + "/foo bar"
+
+	// create a replication cursor to make pruning work at all
+	_, err = endpoint.CreateReplicationCursor(ctx, fs, fsversion(ctx, fs, "@2"), senderJid)
+	require.NoError(ctx, err)
+
+	// create step holds for the incremental @2->@3
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@2"), senderJid)
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@3"), senderJid)
+	// create step holds for another job
+	otherJid := endpoint.MustMakeJobID("other-job")
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@2"), otherJid)
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@3"), otherJid)
+
+	p := prunerFactory.BuildSenderPruner(ctx, sender, sender)
+
+	p.Prune()
+
+	report := p.Report()
+
+	reportJSON, err := json.MarshalIndent(report, "", "  ")
+	require.NoError(ctx, err)
+	ctx.Logf("%s\n", string(reportJSON))
+
+	require.Equal(ctx, pruner.Done.String(), report.State)
+	require.Len(ctx, report.Completed, 1)
+	fsReport := report.Completed[0]
+	require.Equal(ctx, fs, fsReport.Filesystem)
+	require.Empty(ctx, fsReport.SkipReason)
+	require.Empty(ctx, fsReport.LastError)
+	expectDestroyList := []pruner.SnapshotReport{
+		{
+			Name:       "1",
+			Replicated: true,
+		},
+		{
+			Name:       "2",
+			Replicated: true,
+		},
+		{
+			Name:       "3",
+			Replicated: true,
+		},
+		{
+			Name:       "4",
+			Replicated: true,
+		},
+	}
+	for _, d := range fsReport.DestroyList {
+		d.Date = time.Time{}
+	}
+	require.Subset(ctx, fsReport.DestroyList, expectDestroyList)
+}
+
+
+
+func PrunerNoKeepNotReplicatedButKeepStepHold(ctx *platformtest.Context) {
+
+	platformtest.Run(ctx, platformtest.PanicErr, ctx.RootDataset, `
+        DESTROYROOT
+        CREATEROOT
+        +  "foo bar"
+        +  "foo bar@1"
+        +  "foo bar@2"
+        +  "foo bar@3"
+        +  "foo bar@4"
+        +  "foo bar@5"
+    `)
+
+	c, err := config.ParseConfigBytes([]byte(fmt.Sprintf(`
+jobs:
+- name: prunetest
+  type: push
+  filesystems: {
+      "%s/foo bar<": true
+  }
+  connect:
+    type: tcp
+    address: 255.255.255.255:255
+  snapshotting:
+    type: manual
+  pruning:
+    keep_sender:
+    - type: step_holds
+    - type: last_n
+      count: 1
+    keep_receiver:
+    - type: last_n
+      count: 2
+    `, ctx.RootDataset)))
+	require.NoError(ctx, err)
+
+	pushJob := c.Jobs[0].Ret.(*config.PushJob)
+
+	dummyHistVec := prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "foo",
+		Subsystem: "foo",
+		Name:      "foo",
+		Help:      "foo",
+	}, []string{"foo"})
+
+	prunerFactory, err := pruner.NewPrunerFactory(pushJob.Pruning, dummyHistVec)
+	require.NoError(ctx, err)
+
+	senderJid := endpoint.MustMakeJobID("sender-job")
+
+	fsfilter, err := filters.DatasetMapFilterFromConfig(pushJob.Filesystems)
+	require.NoError(ctx, err)
+
+	sender := endpoint.NewSender(endpoint.SenderConfig{
+		FSF: fsfilter,
+		Encrypt: &zfs.NilBool{
+			B: false,
+		},
+        JobID: senderJid,
+	})
+
+	fs := ctx.RootDataset + "/foo bar"
+
+	// create a replication cursor to make pruning work at all
+	_, err = endpoint.CreateReplicationCursor(ctx, fs, fsversion(ctx, fs, "@2"), senderJid)
+	require.NoError(ctx, err)
+
+	// create step holds for the incremental @2->@3
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@2"), senderJid)
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@3"), senderJid)
+	// create step holds for another job
+	otherJid := endpoint.MustMakeJobID("other-job")
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@2"), otherJid)
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@3"), otherJid)
+
+	p := prunerFactory.BuildSenderPruner(ctx, sender, sender)
+
+	p.Prune()
+
+	report := p.Report()
+
+	reportJSON, err := json.MarshalIndent(report, "", "  ")
+	require.NoError(ctx, err)
+	ctx.Logf("%s\n", string(reportJSON))
+
+	require.Equal(ctx, pruner.Done.String(), report.State)
+	require.Len(ctx, report.Completed, 1)
+	fsReport := report.Completed[0]
+	require.Equal(ctx, fs, fsReport.Filesystem)
+	require.Empty(ctx, fsReport.SkipReason)
+	require.Empty(ctx, fsReport.LastError)
+	expectDestroyList := []pruner.SnapshotReport{
+		{
+			Name:       "1",
+			Replicated: true,
+		},
+		{
+			Name:       "4",
+			Replicated: true,
+		},
+	}
+	for _, d := range fsReport.DestroyList {
+		d.Date = time.Time{}
+	}
+	require.Subset(ctx, fsReport.DestroyList, expectDestroyList)
+}
--- a/platformtest/tests/pruner.v2.go
+++ b/platformtest/tests/pruner.v2.go
@ -0,0 +1,137 @@
+package tests
+
+import (
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/kr/pretty"
+	"github.com/stretchr/testify/require"
+	"github.com/zrepl/zrepl/config"
+	"github.com/zrepl/zrepl/daemon/filters"
+	"github.com/zrepl/zrepl/daemon/pruner.v2"
+	"github.com/zrepl/zrepl/endpoint"
+	"github.com/zrepl/zrepl/platformtest"
+	"github.com/zrepl/zrepl/pruning"
+	"github.com/zrepl/zrepl/zfs"
+)
+
+func Pruner2NotReplicated(ctx *platformtest.Context) {
+
+	platformtest.Run(ctx, platformtest.PanicErr, ctx.RootDataset, `
+        DESTROYROOT
+        CREATEROOT
+        +  "foo bar"
+        +  "foo bar@1"
+        +  "foo bar@2"
+        +  "foo bar@3"
+        +  "foo bar@4"
+        +  "foo bar@5"
+	`)
+
+	fs := ctx.RootDataset + "/foo bar"
+	senderJid := endpoint.MustMakeJobID("sender-job")
+	otherJid1 := endpoint.MustMakeJobID("other-job-1")
+	otherJid2 := endpoint.MustMakeJobID("other-job-2")
+
+
+	// create step holds for the incremental @2->@3
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@2"), senderJid)
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@3"), senderJid)
+	// create step holds for other-job-1 @2 -> @3
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@2"), otherJid1)
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@3"), otherJid1)
+	// create step hold for other-job-2 @1 (will be pruned)
+	endpoint.HoldStep(ctx, fs, fsversion(ctx, fs, "@1"), otherJid2)
+
+	c, err := config.ParseConfigBytes([]byte(fmt.Sprintf(`
+jobs:
+- name: prunetest
+  type: push
+  filesystems: {
+      "%s/foo bar": true
+  }
+  connect:
+    type: tcp
+    address: 255.255.255.255:255
+  snapshotting:
+    type: manual
+  pruning:
+    keep_sender:
+    #- type: not_replicated
+    - type: step_holds
+    - type: last_n
+      count: 1
+    keep_receiver:
+    - type: last_n
+      count: 2
+    `, ctx.RootDataset)))
+	require.NoError(ctx, err)
+
+	pushJob := c.Jobs[0].Ret.(*config.PushJob)
+
+	require.NoError(ctx, err)
+
+	fsfilter, err := filters.DatasetMapFilterFromConfig(pushJob.Filesystems)
+	require.NoError(ctx, err)
+
+	matchedFilesystems, err := zfs.ZFSListMapping(ctx, fsfilter)
+	ctx.Logf("%s", pretty.Sprint(matchedFilesystems))
+	require.NoError(ctx, err)
+	require.Len(ctx, matchedFilesystems, 1)
+
+	sideSender := pruner.NewSideSender(senderJid)
+
+	keepRules, err := pruning.RulesFromConfig(senderJid, pushJob.Pruning.KeepSender)
+	require.NoError(ctx, err)
+	p := pruner.NewPruner(fsfilter, senderJid, sideSender, keepRules)
+
+	runDone := make(chan *pruner.Report)
+	go func() {
+		runDone <- p.Run(ctx)
+	}()
+
+	var report *pruner.Report
+	// concurrency stress
+out:
+	for {
+		select {
+		case <-time.After(10 * time.Millisecond):
+			p.Report(ctx)
+		case report = <-runDone:
+			break out
+		}
+	}
+	ctx.Logf("%s\n", pretty.Sprint(report))
+
+	reportJSON, err := json.MarshalIndent(report, "", "  ")
+	require.NoError(ctx, err)
+	ctx.Logf("%s\n", string(reportJSON))
+
+	ctx.FailNow()
+	// fs := ctx.RootDataset + "/foo bar"
+
+	// // create a replication cursor to make pruning work at all
+	// _, err = endpoint.CreateReplicationCursor(ctx, fs, fsversion(ctx, fs, "@2"), senderJid)
+	// require.NoError(ctx, err)
+
+	// p := prunerFactory.BuildSenderPruner(ctx, sender, sender)
+
+	// p.Prune()
+
+	// report := p.Report()
+
+	// require.Equal(ctx, pruner.Done.String(), report.State)
+	// require.Len(ctx, report.Completed, 1)
+	// fsReport := report.Completed[0]
+	// require.Equal(ctx, fs, fsReport.Filesystem)
+	// require.Empty(ctx, fsReport.SkipReason)
+	// require.Empty(ctx, fsReport.LastError)
+	// require.Len(ctx, fsReport.DestroyList, 1)
+	// require.Equal(ctx, fsReport.DestroyList[0], pruner.SnapshotReport{
+	// 	Name:       "1",
+	// 	Replicated: true,
+	// 	Date:       fsReport.DestroyList[0].Date,
+	// })
+
+}
--- a/platformtest/tests/undestroyableSnapshotParsing.go
+++ b/platformtest/tests/undestroyableSnapshotParsing.go
@ -17,10 +17,12 @@ func UndestroyableSnapshotParsing(t *platformtest.Context) {
 		+  "foo bar@1 2 3"
 		+  "foo bar@4 5 6"
 		+  "foo bar@7 8 9"
+		+  "foo bar@10 11 12"
 		R  zfs hold zrepl_platformtest "${ROOTDS}/foo bar@4 5 6"
+		R  zfs hold zrepl_platformtest "${ROOTDS}/foo bar@7 8 9"
 	`)

-	err := zfs.ZFSDestroy(t, fmt.Sprintf("%s/foo bar@1 2 3,4 5 6,7 8 9", t.RootDataset))
+	err := zfs.ZFSDestroy(t, fmt.Sprintf("%s/foo bar@1 2 3,4 5 6,7 8 9,10 11 12", t.RootDataset))
 	if err == nil {
 		panic("expecting destroy error due to hold")
 	}
@ -30,8 +32,9 @@ func UndestroyableSnapshotParsing(t *platformtest.Context) {
 		if dse.Filesystem != fmt.Sprintf("%s/foo bar", t.RootDataset) {
 			panic(dse.Filesystem)
 		}
-		require.Equal(t, []string{"4 5 6"}, dse.Undestroyable)
-		require.Equal(t, []string{"dataset is busy"}, dse.Reason)
+		expectUndestroyable := []string{"4 5 6", "7 8 9"}
+		require.Len(t, dse.Undestroyable, len(expectUndestroyable))
+		require.Subset(t, dse.Undestroyable, expectUndestroyable)
 	}

 }
--- a/pruning/keep_grid.go
+++ b/pruning/keep_grid.go
@ -66,24 +66,26 @@ type retentionGridAdaptor struct {
 	Snapshot
 }

+func (a retentionGridAdaptor) Date() time.Time { return a.Snapshot.GetCreation() }
+
 func (a retentionGridAdaptor) LessThan(b retentiongrid.Entry) bool {
 	return a.Date().Before(b.Date())
 }

 // Prune filters snapshots with the retention grid.
-func (p *KeepGrid) KeepRule(snaps []Snapshot) (destroyList []Snapshot) {
+func (p *KeepGrid) KeepRule(snaps []Snapshot) PruneSnapshotsResult {

-	snaps = filterSnapList(snaps, func(snapshot Snapshot) bool {
-		return p.re.MatchString(snapshot.Name())
+	reCandidates := partitionSnapList(snaps, func(snapshot Snapshot) bool {
+		return p.re.MatchString(snapshot.GetName())
 	})
-	if len(snaps) == 0 {
-		return nil
+	if len(reCandidates.Remove) == 0 {
+		return reCandidates
 	}

 	// Build adaptors for retention grid
 	adaptors := make([]retentiongrid.Entry, 0)
 	for i := range snaps {
-		adaptors = append(adaptors, retentionGridAdaptor{snaps[i]})
+		adaptors = append(adaptors, retentionGridAdaptor{reCandidates.Remove[i]})
 	}

 	// determine 'now' edge
@ -93,12 +95,17 @@ func (p *KeepGrid) KeepRule(snaps []Snapshot) (destroyList []Snapshot) {
 	now := adaptors[len(adaptors)-1].Date()

 	// Evaluate retention grid
-	_, removea := p.retentionGrid.FitEntries(now, adaptors)
+	keepa, removea := p.retentionGrid.FitEntries(now, adaptors)

 	// Revert adaptors
-	destroyList = make([]Snapshot, len(removea))
+	destroyList := make([]Snapshot, len(removea))
 	for i := range removea {
 		destroyList[i] = removea[i].(retentionGridAdaptor).Snapshot
 	}
-	return destroyList
+	for _, a := range keepa {
+		reCandidates.Keep = append(reCandidates.Keep, a.(retentionGridAdaptor))
+	}
+	reCandidates.Remove = destroyList
+
+	return reCandidates
 }
--- a/pruning/keep_helpers.go
+++ b/pruning/keep_helpers.go
@ -1,10 +1,13 @@
 package pruning

-func filterSnapList(snaps []Snapshot, predicate func(Snapshot) bool) []Snapshot {
-	r := make([]Snapshot, 0, len(snaps))
+func partitionSnapList(snaps []Snapshot, remove func(Snapshot) bool) (r PruneSnapshotsResult) {
+	r.Keep = make([]Snapshot, 0, len(snaps))
+	r.Remove = make([]Snapshot, 0, len(snaps))
 	for i := range snaps {
-		if predicate(snaps[i]) {
-			r = append(r, snaps[i])
+		if remove(snaps[i]) {
+			r.Remove = append(r.Remove, snaps[i])
+		} else {
+			r.Keep = append(r.Keep, snaps[i])
 		}
 	}
 	return r
--- a/pruning/keep_last_n.go
+++ b/pruning/keep_last_n.go
@ -17,17 +17,17 @@ func NewKeepLastN(n int) (*KeepLastN, error) {
 	return &KeepLastN{n}, nil
 }

-func (k KeepLastN) KeepRule(snaps []Snapshot) (destroyList []Snapshot) {
+func (k KeepLastN) KeepRule(snaps []Snapshot) PruneSnapshotsResult {

 	if k.n > len(snaps) {
-		return []Snapshot{}
+		return PruneSnapshotsResult{Keep: snaps}
 	}

 	res := shallowCopySnapList(snaps)

 	sort.Slice(res, func(i, j int) bool {
-		return res[i].Date().After(res[j].Date())
+		return res[i].GetCreateTXG() > res[j].GetCreateTXG()
 	})

-	return res[k.n:]
+	return PruneSnapshotsResult{Remove: res[k.n:], Keep: res[:k.n]}
 }
--- a/pruning/keep_not_replicated.go
+++ b/pruning/keep_not_replicated.go
@ -2,8 +2,8 @@ package pruning

 type KeepNotReplicated struct{}

-func (*KeepNotReplicated) KeepRule(snaps []Snapshot) (destroyList []Snapshot) {
-	return filterSnapList(snaps, func(snapshot Snapshot) bool {
+func (*KeepNotReplicated) KeepRule(snaps []Snapshot) PruneSnapshotsResult {
+	return partitionSnapList(snaps, func(snapshot Snapshot) bool {
 		return snapshot.Replicated()
 	})
 }
--- a/pruning/keep_regex.go
+++ b/pruning/keep_regex.go
@ -27,12 +27,12 @@ func MustKeepRegex(expr string, negate bool) *KeepRegex {
 	return k
 }

-func (k *KeepRegex) KeepRule(snaps []Snapshot) []Snapshot {
-	return filterSnapList(snaps, func(s Snapshot) bool {
+func (k *KeepRegex) KeepRule(snaps []Snapshot) PruneSnapshotsResult {
+	return partitionSnapList(snaps, func(s Snapshot) bool {
 		if k.negate {
-			return k.expr.FindStringIndex(s.Name()) != nil
+			return k.expr.FindStringIndex(s.GetName()) != nil
 		} else {
-			return k.expr.FindStringIndex(s.Name()) == nil
+			return k.expr.FindStringIndex(s.GetName()) == nil
 		}
 	})
 }
--- a/pruning/keep_step_holds.go
+++ b/pruning/keep_step_holds.go
@ -0,0 +1,44 @@
+package pruning
+
+import (
+	"github.com/pkg/errors"
+	"github.com/zrepl/zrepl/endpoint"
+)
+
+type KeepStepHolds struct {
+	keepJobIDs map[endpoint.JobID]bool
+}
+
+var _ KeepRule = (*KeepStepHolds)(nil)
+
+func NewKeepStepHolds(mainJobId endpoint.JobID, additionalJobIdsStrings []string) (_ *KeepStepHolds, err error) {
+	additionalJobIds := make(map[endpoint.JobID]bool, len(additionalJobIdsStrings))
+
+	mainJobId.MustValidate()
+	additionalJobIds[mainJobId] = true
+
+	for i := range additionalJobIdsStrings {
+		ajid, err := endpoint.MakeJobID(additionalJobIdsStrings[i])
+		if err != nil {
+			return nil, errors.WithMessagef(err, "cannot parse job id %q: %s", additionalJobIdsStrings[i])
+		}
+		if additionalJobIds[ajid] == true {
+			return nil, errors.Errorf("duplicate job id %q", ajid)
+		}
+	}
+	return &KeepStepHolds{additionalJobIds}, nil
+}
+
+func (h *KeepStepHolds) KeepRule(snaps []Snapshot) PruneSnapshotsResult {
+	return partitionSnapList(snaps, func(s Snapshot) bool {
+		holdingJobIDs := make(map[endpoint.JobID]bool)
+		for _, h := range s.StepHolds() {
+			holdingJobIDs[h.GetJobID()] = true
+		}
+		oneOrMoreOfOurJobIDsHoldsSnap := false
+		for kjid := range h.keepJobIDs {
+			oneOrMoreOfOurJobIDsHoldsSnap = oneOrMoreOfOurJobIDsHoldsSnap || holdingJobIDs[kjid]
+		}
+		return !oneOrMoreOfOurJobIDsHoldsSnap
+	})
+}
--- a/pruning/pruning.go
+++ b/pruning/pruning.go
@ -7,47 +7,93 @@ import (
 	"github.com/pkg/errors"

 	"github.com/zrepl/zrepl/config"
+	"github.com/zrepl/zrepl/endpoint"
 )

 type KeepRule interface {
-	KeepRule(snaps []Snapshot) (destroyList []Snapshot)
+	KeepRule(snaps []Snapshot) PruneSnapshotsResult
 }

 type Snapshot interface {
-	Name() string
+	GetName() string
 	Replicated() bool
-	Date() time.Time
+	GetCreation() time.Time
+	GetCreateTXG() uint64
+	StepHolds() []StepHold
 }

-// The returned snapshot list is guaranteed to only contains elements of input parameter snaps
-func PruneSnapshots(snaps []Snapshot, keepRules []KeepRule) []Snapshot {
+type StepHold interface {
+	GetJobID() endpoint.JobID
+}
+
+type PruneSnapshotsResult struct {
+	Remove, Keep []Snapshot
+}
+
+// The returned snapshot results are a partition of the snaps argument.
+// That means than len(Remove) + len(Keep) == len(snaps)
+func PruneSnapshots(snapsI []Snapshot, keepRules []KeepRule) PruneSnapshotsResult {

 	if len(keepRules) == 0 {
-		return []Snapshot{}
+		return PruneSnapshotsResult{Remove: nil, Keep: snapsI}
+	}
+
+	type snapshot struct {
+		Snapshot
+		keepCount, removeCount int
+	}
+
+	// project down to snapshot
+	snaps := make([]Snapshot, len(snapsI))
+	for i := range snaps {
+		snaps[i] = &snapshot{snapsI[i], 0, 0}
 	}

-	remCount := make(map[Snapshot]int, len(snaps))
 	for _, r := range keepRules {
-		ruleRems := r.KeepRule(snaps)
-		for _, ruleRem := range ruleRems {
-			remCount[ruleRem]++
+
+		ruleImplCheckSet := make(map[Snapshot]int, len(snaps))
+		for _, s := range snaps {
+			ruleImplCheckSet[s] = ruleImplCheckSet[s] + 1
+		}
+
+		ruleResults := r.KeepRule(snaps)
+
+		for _, s := range snaps {
+			ruleImplCheckSet[s] = ruleImplCheckSet[s] - 1
+		}
+		for _, n := range ruleImplCheckSet {
+			if n != 0 {
+				panic(fmt.Sprintf("incorrect rule implementation: %T", r))
+			}
+		}
+
+		for _, s := range ruleResults.Remove {
+			s.(*snapshot).removeCount++
+		}
+		for _, s := range ruleResults.Keep {
+			s.(*snapshot).keepCount++
 		}
 	}

 	remove := make([]Snapshot, 0, len(snaps))
-	for snap, rc := range remCount {
-		if rc == len(keepRules) {
-			remove = append(remove, snap)
+	keep := make([]Snapshot, 0, len(snaps))
+	for _, sI := range snaps {
+		s := sI.(*snapshot)
+		if s.removeCount == len(keepRules) {
+			// all keep rules agree to remove the snap
+			remove = append(remove, s.Snapshot)
+		} else {
+			keep = append(keep, s.Snapshot)
 		}
 	}

-	return remove
+	return PruneSnapshotsResult{Remove: remove, Keep: keep}
 }

-func RulesFromConfig(in []config.PruningEnum) (rules []KeepRule, err error) {
+func RulesFromConfig(mainJobId endpoint.JobID, in []config.PruningEnum) (rules []KeepRule, err error) {
 	rules = make([]KeepRule, len(in))
 	for i := range in {
-		rules[i], err = RuleFromConfig(in[i])
+		rules[i], err = RuleFromConfig(mainJobId, in[i])
 		if err != nil {
 			return nil, errors.Wrapf(err, "cannot build rule #%d", i)
 		}
@ -55,7 +101,7 @@ func RulesFromConfig(in []config.PruningEnum) (rules []KeepRule, err error) {
 	return rules, nil
 }

-func RuleFromConfig(in config.PruningEnum) (KeepRule, error) {
+func RuleFromConfig(mainJobId endpoint.JobID, in config.PruningEnum) (KeepRule, error) {
 	switch v := in.Ret.(type) {
 	case *config.PruneKeepNotReplicated:
 		return NewKeepNotReplicated(), nil
@ -65,6 +111,8 @@ func RuleFromConfig(in config.PruningEnum) (KeepRule, error) {
 		return NewKeepRegex(v.Regex, v.Negate)
 	case *config.PruneGrid:
 		return NewKeepGrid(v)
+	case *config.PruneKeepStepHolds:
+		return NewKeepStepHolds(mainJobId, v.AdditionalJobIds)
 	default:
 		return nil, fmt.Errorf("unknown keep rule type %T", v)
 	}
--- a/replication/logic/pdu/pdu.pb.go
+++ b/replication/logic/pdu/pdu.pb.go
@ -46,7 +46,36 @@ func (x Tri) String() string {
 	return proto.EnumName(Tri_name, int32(x))
 }
 func (Tri) EnumDescriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{0}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{0}
+}
+
+type SendAbstraction_SendAbstractionType int32
+
+const (
+	SendAbstraction_Undefined           SendAbstraction_SendAbstractionType = 0
+	SendAbstraction_ReplicationCursorV2 SendAbstraction_SendAbstractionType = 1
+	SendAbstraction_StepHold            SendAbstraction_SendAbstractionType = 2
+	SendAbstraction_StepBookmark        SendAbstraction_SendAbstractionType = 3
+)
+
+var SendAbstraction_SendAbstractionType_name = map[int32]string{
+	0: "Undefined",
+	1: "ReplicationCursorV2",
+	2: "StepHold",
+	3: "StepBookmark",
+}
+var SendAbstraction_SendAbstractionType_value = map[string]int32{
+	"Undefined":           0,
+	"ReplicationCursorV2": 1,
+	"StepHold":            2,
+	"StepBookmark":        3,
+}
+
+func (x SendAbstraction_SendAbstractionType) String() string {
+	return proto.EnumName(SendAbstraction_SendAbstractionType_name, int32(x))
+}
+func (SendAbstraction_SendAbstractionType) EnumDescriptor() ([]byte, []int) {
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{5, 0}
 }

 type FilesystemVersion_VersionType int32
@ -69,7 +98,7 @@ func (x FilesystemVersion_VersionType) String() string {
 	return proto.EnumName(FilesystemVersion_VersionType_name, int32(x))
 }
 func (FilesystemVersion_VersionType) EnumDescriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{5, 0}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{6, 0}
 }

 type ListFilesystemReq struct {
@ -82,7 +111,7 @@ func (m *ListFilesystemReq) Reset()         { *m = ListFilesystemReq{} }
 func (m *ListFilesystemReq) String() string { return proto.CompactTextString(m) }
 func (*ListFilesystemReq) ProtoMessage()    {}
 func (*ListFilesystemReq) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{0}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{0}
 }
 func (m *ListFilesystemReq) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_ListFilesystemReq.Unmarshal(m, b)
@ -113,7 +142,7 @@ func (m *ListFilesystemRes) Reset()         { *m = ListFilesystemRes{} }
 func (m *ListFilesystemRes) String() string { return proto.CompactTextString(m) }
 func (*ListFilesystemRes) ProtoMessage()    {}
 func (*ListFilesystemRes) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{1}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{1}
 }
 func (m *ListFilesystemRes) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_ListFilesystemRes.Unmarshal(m, b)
@ -154,7 +183,7 @@ func (m *Filesystem) Reset()         { *m = Filesystem{} }
 func (m *Filesystem) String() string { return proto.CompactTextString(m) }
 func (*Filesystem) ProtoMessage()    {}
 func (*Filesystem) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{2}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{2}
 }
 func (m *Filesystem) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_Filesystem.Unmarshal(m, b)
@ -213,7 +242,7 @@ func (m *ListFilesystemVersionsReq) Reset()         { *m = ListFilesystemVersion
 func (m *ListFilesystemVersionsReq) String() string { return proto.CompactTextString(m) }
 func (*ListFilesystemVersionsReq) ProtoMessage()    {}
 func (*ListFilesystemVersionsReq) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{3}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{3}
 }
 func (m *ListFilesystemVersionsReq) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_ListFilesystemVersionsReq.Unmarshal(m, b)
@ -242,6 +271,7 @@ func (m *ListFilesystemVersionsReq) GetFilesystem() string {

 type ListFilesystemVersionsRes struct {
 	Versions             []*FilesystemVersion `protobuf:"bytes,1,rep,name=Versions,proto3" json:"Versions,omitempty"`
+	SendAbstractions     []*SendAbstraction   `protobuf:"bytes,2,rep,name=SendAbstractions,proto3" json:"SendAbstractions,omitempty"`
 	XXX_NoUnkeyedLiteral struct{}             `json:"-"`
 	XXX_unrecognized     []byte               `json:"-"`
 	XXX_sizecache        int32                `json:"-"`
@ -251,7 +281,7 @@ func (m *ListFilesystemVersionsRes) Reset()         { *m = ListFilesystemVersion
 func (m *ListFilesystemVersionsRes) String() string { return proto.CompactTextString(m) }
 func (*ListFilesystemVersionsRes) ProtoMessage()    {}
 func (*ListFilesystemVersionsRes) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{4}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{4}
 }
 func (m *ListFilesystemVersionsRes) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_ListFilesystemVersionsRes.Unmarshal(m, b)
@ -278,6 +308,67 @@ func (m *ListFilesystemVersionsRes) GetVersions() []*FilesystemVersion {
 	return nil
 }

+func (m *ListFilesystemVersionsRes) GetSendAbstractions() []*SendAbstraction {
+	if m != nil {
+		return m.SendAbstractions
+	}
+	return nil
+}
+
+type SendAbstraction struct {
+	Type                 SendAbstraction_SendAbstractionType `protobuf:"varint,1,opt,name=Type,proto3,enum=SendAbstraction_SendAbstractionType" json:"Type,omitempty"`
+	JobID                string                              `protobuf:"bytes,2,opt,name=JobID,proto3" json:"JobID,omitempty"`
+	Version              *FilesystemVersion                  `protobuf:"bytes,3,opt,name=Version,proto3" json:"Version,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}                            `json:"-"`
+	XXX_unrecognized     []byte                              `json:"-"`
+	XXX_sizecache        int32                               `json:"-"`
+}
+
+func (m *SendAbstraction) Reset()         { *m = SendAbstraction{} }
+func (m *SendAbstraction) String() string { return proto.CompactTextString(m) }
+func (*SendAbstraction) ProtoMessage()    {}
+func (*SendAbstraction) Descriptor() ([]byte, []int) {
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{5}
+}
+func (m *SendAbstraction) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_SendAbstraction.Unmarshal(m, b)
+}
+func (m *SendAbstraction) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_SendAbstraction.Marshal(b, m, deterministic)
+}
+func (dst *SendAbstraction) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_SendAbstraction.Merge(dst, src)
+}
+func (m *SendAbstraction) XXX_Size() int {
+	return xxx_messageInfo_SendAbstraction.Size(m)
+}
+func (m *SendAbstraction) XXX_DiscardUnknown() {
+	xxx_messageInfo_SendAbstraction.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_SendAbstraction proto.InternalMessageInfo
+
+func (m *SendAbstraction) GetType() SendAbstraction_SendAbstractionType {
+	if m != nil {
+		return m.Type
+	}
+	return SendAbstraction_Undefined
+}
+
+func (m *SendAbstraction) GetJobID() string {
+	if m != nil {
+		return m.JobID
+	}
+	return ""
+}
+
+func (m *SendAbstraction) GetVersion() *FilesystemVersion {
+	if m != nil {
+		return m.Version
+	}
+	return nil
+}
+
 type FilesystemVersion struct {
 	Type                 FilesystemVersion_VersionType `protobuf:"varint,1,opt,name=Type,proto3,enum=FilesystemVersion_VersionType" json:"Type,omitempty"`
 	Name                 string                        `protobuf:"bytes,2,opt,name=Name,proto3" json:"Name,omitempty"`
@ -293,7 +384,7 @@ func (m *FilesystemVersion) Reset()         { *m = FilesystemVersion{} }
 func (m *FilesystemVersion) String() string { return proto.CompactTextString(m) }
 func (*FilesystemVersion) ProtoMessage()    {}
 func (*FilesystemVersion) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{5}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{6}
 }
 func (m *FilesystemVersion) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_FilesystemVersion.Unmarshal(m, b)
@ -371,7 +462,7 @@ func (m *SendReq) Reset()         { *m = SendReq{} }
 func (m *SendReq) String() string { return proto.CompactTextString(m) }
 func (*SendReq) ProtoMessage()    {}
 func (*SendReq) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{6}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{7}
 }
 func (m *SendReq) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_SendReq.Unmarshal(m, b)
@ -445,7 +536,7 @@ func (m *Property) Reset()         { *m = Property{} }
 func (m *Property) String() string { return proto.CompactTextString(m) }
 func (*Property) ProtoMessage()    {}
 func (*Property) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{7}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{8}
 }
 func (m *Property) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_Property.Unmarshal(m, b)
@ -496,7 +587,7 @@ func (m *SendRes) Reset()         { *m = SendRes{} }
 func (m *SendRes) String() string { return proto.CompactTextString(m) }
 func (*SendRes) ProtoMessage()    {}
 func (*SendRes) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{8}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{9}
 }
 func (m *SendRes) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_SendRes.Unmarshal(m, b)
@ -548,7 +639,7 @@ func (m *SendCompletedReq) Reset()         { *m = SendCompletedReq{} }
 func (m *SendCompletedReq) String() string { return proto.CompactTextString(m) }
 func (*SendCompletedReq) ProtoMessage()    {}
 func (*SendCompletedReq) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{9}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{10}
 }
 func (m *SendCompletedReq) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_SendCompletedReq.Unmarshal(m, b)
@ -585,7 +676,7 @@ func (m *SendCompletedRes) Reset()         { *m = SendCompletedRes{} }
 func (m *SendCompletedRes) String() string { return proto.CompactTextString(m) }
 func (*SendCompletedRes) ProtoMessage()    {}
 func (*SendCompletedRes) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{10}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{11}
 }
 func (m *SendCompletedRes) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_SendCompletedRes.Unmarshal(m, b)
@ -620,7 +711,7 @@ func (m *ReceiveReq) Reset()         { *m = ReceiveReq{} }
 func (m *ReceiveReq) String() string { return proto.CompactTextString(m) }
 func (*ReceiveReq) ProtoMessage()    {}
 func (*ReceiveReq) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{11}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{12}
 }
 func (m *ReceiveReq) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_ReceiveReq.Unmarshal(m, b)
@ -671,7 +762,7 @@ func (m *ReceiveRes) Reset()         { *m = ReceiveRes{} }
 func (m *ReceiveRes) String() string { return proto.CompactTextString(m) }
 func (*ReceiveRes) ProtoMessage()    {}
 func (*ReceiveRes) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{12}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{13}
 }
 func (m *ReceiveRes) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_ReceiveRes.Unmarshal(m, b)
@ -704,7 +795,7 @@ func (m *DestroySnapshotsReq) Reset()         { *m = DestroySnapshotsReq{} }
 func (m *DestroySnapshotsReq) String() string { return proto.CompactTextString(m) }
 func (*DestroySnapshotsReq) ProtoMessage()    {}
 func (*DestroySnapshotsReq) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{13}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{14}
 }
 func (m *DestroySnapshotsReq) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_DestroySnapshotsReq.Unmarshal(m, b)
@ -750,7 +841,7 @@ func (m *DestroySnapshotRes) Reset()         { *m = DestroySnapshotRes{} }
 func (m *DestroySnapshotRes) String() string { return proto.CompactTextString(m) }
 func (*DestroySnapshotRes) ProtoMessage()    {}
 func (*DestroySnapshotRes) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{14}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{15}
 }
 func (m *DestroySnapshotRes) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_DestroySnapshotRes.Unmarshal(m, b)
@ -795,7 +886,7 @@ func (m *DestroySnapshotsRes) Reset()         { *m = DestroySnapshotsRes{} }
 func (m *DestroySnapshotsRes) String() string { return proto.CompactTextString(m) }
 func (*DestroySnapshotsRes) ProtoMessage()    {}
 func (*DestroySnapshotsRes) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{15}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{16}
 }
 func (m *DestroySnapshotsRes) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_DestroySnapshotsRes.Unmarshal(m, b)
@ -833,7 +924,7 @@ func (m *ReplicationCursorReq) Reset()         { *m = ReplicationCursorReq{} }
 func (m *ReplicationCursorReq) String() string { return proto.CompactTextString(m) }
 func (*ReplicationCursorReq) ProtoMessage()    {}
 func (*ReplicationCursorReq) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{16}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{17}
 }
 func (m *ReplicationCursorReq) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_ReplicationCursorReq.Unmarshal(m, b)
@ -874,7 +965,7 @@ func (m *ReplicationCursorRes) Reset()         { *m = ReplicationCursorRes{} }
 func (m *ReplicationCursorRes) String() string { return proto.CompactTextString(m) }
 func (*ReplicationCursorRes) ProtoMessage()    {}
 func (*ReplicationCursorRes) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{17}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{18}
 }
 func (m *ReplicationCursorRes) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_ReplicationCursorRes.Unmarshal(m, b)
@ -1010,7 +1101,7 @@ func (m *PingReq) Reset()         { *m = PingReq{} }
 func (m *PingReq) String() string { return proto.CompactTextString(m) }
 func (*PingReq) ProtoMessage()    {}
 func (*PingReq) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{18}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{19}
 }
 func (m *PingReq) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_PingReq.Unmarshal(m, b)
@ -1049,7 +1140,7 @@ func (m *PingRes) Reset()         { *m = PingRes{} }
 func (m *PingRes) String() string { return proto.CompactTextString(m) }
 func (*PingRes) ProtoMessage()    {}
 func (*PingRes) Descriptor() ([]byte, []int) {
-	return fileDescriptor_pdu_483c6918b7b3d747, []int{19}
+	return fileDescriptor_pdu_2d84e8d7d278a80d, []int{20}
 }
 func (m *PingRes) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_PingRes.Unmarshal(m, b)
@ -1082,6 +1173,7 @@ func init() {
 	proto.RegisterType((*Filesystem)(nil), "Filesystem")
 	proto.RegisterType((*ListFilesystemVersionsReq)(nil), "ListFilesystemVersionsReq")
 	proto.RegisterType((*ListFilesystemVersionsRes)(nil), "ListFilesystemVersionsRes")
+	proto.RegisterType((*SendAbstraction)(nil), "SendAbstraction")
 	proto.RegisterType((*FilesystemVersion)(nil), "FilesystemVersion")
 	proto.RegisterType((*SendReq)(nil), "SendReq")
 	proto.RegisterType((*Property)(nil), "Property")
@ -1098,6 +1190,7 @@ func init() {
 	proto.RegisterType((*PingReq)(nil), "PingReq")
 	proto.RegisterType((*PingRes)(nil), "PingRes")
 	proto.RegisterEnum("Tri", Tri_name, Tri_value)
+	proto.RegisterEnum("SendAbstraction_SendAbstractionType", SendAbstraction_SendAbstractionType_name, SendAbstraction_SendAbstractionType_value)
 	proto.RegisterEnum("FilesystemVersion_VersionType", FilesystemVersion_VersionType_name, FilesystemVersion_VersionType_value)
 }

@ -1338,61 +1431,67 @@ var _Replication_serviceDesc = grpc.ServiceDesc{
 	Metadata: "pdu.proto",
 }

-func init() { proto.RegisterFile("pdu.proto", fileDescriptor_pdu_483c6918b7b3d747) }
+func init() { proto.RegisterFile("pdu.proto", fileDescriptor_pdu_2d84e8d7d278a80d) }

-var fileDescriptor_pdu_483c6918b7b3d747 = []byte{
-	// 833 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x8c, 0x56, 0x5f, 0x6f, 0xe3, 0x44,
-	0x10, 0xaf, 0x13, 0xa7, 0x75, 0x26, 0x3d, 0x2e, 0x9d, 0x96, 0x93, 0xb1, 0xe0, 0x54, 0x2d, 0x08,
-	0xe5, 0x2a, 0x61, 0xa1, 0xf2, 0x47, 0x42, 0x48, 0x27, 0xd1, 0xb4, 0xbd, 0x3b, 0x01, 0x47, 0xb4,
-	0x35, 0x27, 0x74, 0x6f, 0x26, 0x19, 0xb5, 0x56, 0x1d, 0xaf, 0xbb, 0xe3, 0xa0, 0x0b, 0xe2, 0x89,
-	0x47, 0xbe, 0x1e, 0x7c, 0x10, 0x3e, 0x02, 0xf2, 0xc6, 0x4e, 0x9c, 0xd8, 0x41, 0x79, 0xca, 0xce,
-	0x6f, 0x66, 0x77, 0x67, 0x7f, 0xf3, 0x9b, 0x71, 0xa0, 0x9b, 0x4e, 0x66, 0x7e, 0xaa, 0x55, 0xa6,
-	0xc4, 0x31, 0x1c, 0xfd, 0x10, 0x71, 0x76, 0x1d, 0xc5, 0xc4, 0x73, 0xce, 0x68, 0x2a, 0xe9, 0x41,
-	0x5c, 0xd4, 0x41, 0xc6, 0xcf, 0xa0, 0xb7, 0x02, 0xd8, 0xb5, 0x4e, 0xdb, 0x83, 0xde, 0x79, 0xcf,
-	0xaf, 0x04, 0x55, 0xfd, 0xe2, 0x2f, 0x0b, 0x60, 0x65, 0x23, 0x82, 0x3d, 0x0a, 0xb3, 0x3b, 0xd7,
-	0x3a, 0xb5, 0x06, 0x5d, 0x69, 0xd6, 0x78, 0x0a, 0x3d, 0x49, 0x3c, 0x9b, 0x52, 0xa0, 0xee, 0x29,
-	0x71, 0x5b, 0xc6, 0x55, 0x85, 0xf0, 0x13, 0x78, 0xf4, 0x8a, 0x47, 0x71, 0x38, 0xa6, 0x3b, 0x15,
-	0x4f, 0x48, 0xbb, 0xed, 0x53, 0x6b, 0xe0, 0xc8, 0x75, 0x30, 0x3f, 0xe7, 0x15, 0x5f, 0x25, 0x63,
-	0x3d, 0x4f, 0x33, 0x9a, 0xb8, 0xb6, 0x89, 0xa9, 0x42, 0xe2, 0x5b, 0xf8, 0x60, 0xfd, 0x41, 0x6f,
-	0x48, 0x73, 0xa4, 0x12, 0x96, 0xf4, 0x80, 0x4f, 0xab, 0x89, 0x16, 0x09, 0x56, 0x10, 0xf1, 0xfd,
-	0xf6, 0xcd, 0x8c, 0x3e, 0x38, 0xa5, 0x59, 0x50, 0x82, 0x7e, 0x2d, 0x52, 0x2e, 0x63, 0xc4, 0x3f,
-	0x16, 0x1c, 0xd5, 0xfc, 0x78, 0x0e, 0x76, 0x30, 0x4f, 0xc9, 0x5c, 0xfe, 0xde, 0xf9, 0xd3, 0xfa,
-	0x09, 0x7e, 0xf1, 0x9b, 0x47, 0x49, 0x13, 0x9b, 0x33, 0xfa, 0x3a, 0x9c, 0x52, 0x41, 0x9b, 0x59,
-	0xe7, 0xd8, 0x8b, 0x59, 0x34, 0x31, 0x34, 0xd9, 0xd2, 0xac, 0xf1, 0x43, 0xe8, 0x0e, 0x35, 0x85,
-	0x19, 0x05, 0xbf, 0xbc, 0x30, 0xdc, 0xd8, 0x72, 0x05, 0xa0, 0x07, 0x8e, 0x31, 0x22, 0x95, 0xb8,
-	0x1d, 0x73, 0xd2, 0xd2, 0x16, 0xcf, 0xa0, 0x57, 0xb9, 0x16, 0x0f, 0xc1, 0xb9, 0x49, 0xc2, 0x94,
-	0xef, 0x54, 0xd6, 0xdf, 0xcb, 0xad, 0x0b, 0xa5, 0xee, 0xa7, 0xa1, 0xbe, 0xef, 0x5b, 0xe2, 0x6f,
-	0x0b, 0x0e, 0x6e, 0x28, 0x99, 0xec, 0xc0, 0x27, 0x7e, 0x0a, 0xf6, 0xb5, 0x56, 0x53, 0x93, 0x78,
-	0x33, 0x5d, 0xc6, 0x8f, 0x02, 0x5a, 0x81, 0x32, 0x4f, 0x69, 0x8e, 0x6a, 0x05, 0x6a, 0x53, 0x42,
-	0x76, 0x5d, 0x42, 0x02, 0xba, 0x2b, 0x69, 0x74, 0x0c, 0xbf, 0xb6, 0x1f, 0xe8, 0x48, 0xae, 0x60,
-	0x7c, 0x02, 0xfb, 0x97, 0x7a, 0x2e, 0x67, 0x89, 0xbb, 0x6f, 0xb4, 0x53, 0x58, 0xe2, 0x4b, 0x70,
-	0x46, 0x5a, 0xa5, 0xa4, 0xb3, 0xf9, 0x92, 0x6e, 0xab, 0x42, 0xf7, 0x09, 0x74, 0xde, 0x84, 0xf1,
-	0xac, 0xac, 0xc1, 0xc2, 0x10, 0x7f, 0x2e, 0xb9, 0x60, 0x1c, 0xc0, 0xe3, 0x9f, 0x99, 0x26, 0x9b,
-	0x32, 0x77, 0xe4, 0x26, 0x8c, 0x02, 0x0e, 0xaf, 0xde, 0xa5, 0x34, 0xce, 0x68, 0x72, 0x13, 0xfd,
-	0x4e, 0xe6, 0xdd, 0x6d, 0xb9, 0x86, 0xe1, 0x33, 0x80, 0x22, 0x9f, 0x88, 0xd8, 0xb5, 0x8d, 0xdc,
-	0xba, 0x7e, 0x99, 0xa2, 0xac, 0x38, 0xc5, 0x73, 0xe8, 0xe7, 0x39, 0x0c, 0xd5, 0x34, 0x8d, 0x29,
-	0x23, 0x53, 0x98, 0x33, 0xe8, 0xfd, 0xa4, 0xa3, 0xdb, 0x28, 0x09, 0x63, 0x49, 0x0f, 0x05, 0xff,
-	0x8e, 0x5f, 0xd4, 0x4d, 0x56, 0x9d, 0x02, 0x6b, 0xfb, 0x59, 0xfc, 0x01, 0x20, 0x69, 0x4c, 0xd1,
-	0x6f, 0xb4, 0x4b, 0x99, 0x17, 0xe5, 0x6b, 0xfd, 0x6f, 0xf9, 0xce, 0xa0, 0x3f, 0x8c, 0x29, 0xd4,
-	0x55, 0x7e, 0x16, 0x2d, 0x5e, 0xc3, 0xc5, 0x61, 0xe5, 0x76, 0x16, 0xb7, 0x70, 0x7c, 0x49, 0x9c,
-	0x69, 0x35, 0x2f, 0x35, 0xb9, 0x4b, 0x2f, 0xe3, 0xe7, 0xd0, 0x5d, 0xc6, 0xbb, 0xad, 0xad, 0xfd,
-	0xba, 0x0a, 0x12, 0x6f, 0x01, 0x37, 0x2e, 0x2a, 0xda, 0xbe, 0x34, 0xcd, 0x2d, 0x5b, 0xda, 0xbe,
-	0x8c, 0xc9, 0x95, 0x72, 0xa5, 0xb5, 0xd2, 0xa5, 0x52, 0x8c, 0x21, 0x2e, 0x9b, 0x1e, 0x91, 0x4f,
-	0xda, 0x83, 0xfc, 0xe1, 0x71, 0x56, 0x8e, 0x94, 0x63, 0xbf, 0x9e, 0x82, 0x2c, 0x63, 0xc4, 0xd7,
-	0x70, 0x22, 0x29, 0x8d, 0xa3, 0xb1, 0xe9, 0xda, 0xe1, 0x4c, 0xb3, 0xd2, 0xbb, 0xcc, 0xb5, 0xa0,
-	0x71, 0x1f, 0xe3, 0x49, 0x31, 0x44, 0xf2, 0x1d, 0xf6, 0xcb, 0xbd, 0xe5, 0x18, 0x71, 0x5e, 0xab,
-	0x8c, 0xde, 0x45, 0x9c, 0x2d, 0x24, 0xfc, 0x72, 0x4f, 0x2e, 0x91, 0x0b, 0x07, 0xf6, 0x17, 0xe9,
-	0x88, 0x8f, 0xe1, 0x60, 0x14, 0x25, 0xb7, 0x79, 0x02, 0x2e, 0x1c, 0xfc, 0x48, 0xcc, 0xe1, 0x6d,
-	0xd9, 0x35, 0xa5, 0x29, 0x3e, 0x2a, 0x83, 0x38, 0xef, 0xab, 0xab, 0xf1, 0x9d, 0x2a, 0xfb, 0x2a,
-	0x5f, 0x9f, 0x0d, 0xa0, 0x1d, 0xe8, 0x28, 0x1f, 0x31, 0x97, 0x2a, 0xc9, 0x86, 0xa1, 0xa6, 0xfe,
-	0x1e, 0x76, 0xa1, 0x73, 0x1d, 0xc6, 0x4c, 0x7d, 0x0b, 0x1d, 0xb0, 0x03, 0x3d, 0xa3, 0x7e, 0xeb,
-	0xfc, 0xdf, 0x56, 0x3e, 0x00, 0x96, 0x8f, 0x40, 0x0f, 0xec, 0xfc, 0x60, 0x74, 0xfc, 0x22, 0x09,
-	0xaf, 0x5c, 0x31, 0x7e, 0x03, 0x8f, 0xd7, 0xe7, 0x38, 0x23, 0xfa, 0xb5, 0x8f, 0x9f, 0x57, 0xc7,
-	0x18, 0x47, 0xf0, 0xa4, 0xf9, 0x13, 0x80, 0x9e, 0xbf, 0xf5, 0xc3, 0xe2, 0x6d, 0xf7, 0x31, 0x3e,
-	0x87, 0xfe, 0x66, 0xe9, 0xf1, 0xc4, 0x6f, 0x90, 0xb4, 0xd7, 0x84, 0x32, 0x7e, 0x07, 0x47, 0xb5,
-	0xe2, 0xe1, 0xfb, 0x7e, 0x93, 0x10, 0xbc, 0x46, 0x98, 0xf1, 0x2b, 0x78, 0xb4, 0xd6, 0xe2, 0x78,
-	0xe4, 0x6f, 0x8e, 0x0c, 0xaf, 0x06, 0xf1, 0x45, 0xe7, 0x6d, 0x3b, 0x9d, 0xcc, 0x7e, 0xdd, 0x37,
-	0xff, 0x1f, 0xbe, 0xf8, 0x2f, 0x00, 0x00, 0xff, 0xff, 0x27, 0x95, 0xc1, 0x78, 0x4c, 0x08, 0x00,
-	0x00,
+var fileDescriptor_pdu_2d84e8d7d278a80d = []byte{
+	// 940 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x8c, 0x56, 0x6d, 0x6f, 0xe3, 0xc4,
+	0x13, 0xaf, 0x13, 0xa7, 0x75, 0x26, 0xed, 0xbf, 0xee, 0x24, 0xff, 0x23, 0x44, 0x70, 0xaa, 0x96,
+	0x13, 0xca, 0x55, 0x60, 0xa1, 0xf0, 0x20, 0x10, 0xe8, 0xa4, 0x6b, 0xd2, 0x5e, 0x8b, 0xe0, 0x88,
+	0xb6, 0xb9, 0x0a, 0x9d, 0xc4, 0x0b, 0x37, 0x1e, 0x5a, 0xab, 0x8e, 0xd7, 0xdd, 0x75, 0xd0, 0x05,
+	0xf1, 0x8a, 0x77, 0xf0, 0xf5, 0xe0, 0x73, 0x20, 0x3e, 0x02, 0xf2, 0xc6, 0x4e, 0x1c, 0xdb, 0x3d,
+	0xf5, 0x55, 0x76, 0x7e, 0x33, 0xe3, 0x9d, 0xc7, 0xdf, 0x06, 0x9a, 0x91, 0x37, 0x77, 0x22, 0x29,
+	0x62, 0xc1, 0xda, 0x70, 0xf0, 0x9d, 0xaf, 0xe2, 0x53, 0x3f, 0x20, 0xb5, 0x50, 0x31, 0xcd, 0x38,
+	0xdd, 0xb1, 0xe3, 0x32, 0xa8, 0xf0, 0x63, 0x68, 0xad, 0x01, 0xd5, 0x35, 0x0e, 0xeb, 0xfd, 0xd6,
+	0xa0, 0xe5, 0xe4, 0x8c, 0xf2, 0x7a, 0xf6, 0xa7, 0x01, 0xb0, 0x96, 0x11, 0xc1, 0x1c, 0xbb, 0xf1,
+	0x4d, 0xd7, 0x38, 0x34, 0xfa, 0x4d, 0xae, 0xcf, 0x78, 0x08, 0x2d, 0x4e, 0x6a, 0x3e, 0xa3, 0x89,
+	0xb8, 0xa5, 0xb0, 0x5b, 0xd3, 0xaa, 0x3c, 0x84, 0x4f, 0x60, 0xef, 0x5c, 0x8d, 0x03, 0x77, 0x4a,
+	0x37, 0x22, 0xf0, 0x48, 0x76, 0xeb, 0x87, 0x46, 0xdf, 0xe2, 0x9b, 0x60, 0xf2, 0x9d, 0x73, 0x75,
+	0x12, 0x4e, 0xe5, 0x22, 0x8a, 0xc9, 0xeb, 0x9a, 0xda, 0x26, 0x0f, 0xb1, 0xaf, 0xe1, 0xdd, 0xcd,
+	0x84, 0x2e, 0x49, 0x2a, 0x5f, 0x84, 0x8a, 0xd3, 0x1d, 0x3e, 0xce, 0x07, 0x9a, 0x06, 0x98, 0x43,
+	0xd8, 0x1f, 0xc6, 0xfd, 0xde, 0x0a, 0x1d, 0xb0, 0x32, 0x31, 0xad, 0x09, 0x3a, 0x25, 0x4b, 0xbe,
+	0xb2, 0xc1, 0x6f, 0xc0, 0xbe, 0xa0, 0xd0, 0x7b, 0x7e, 0xa5, 0x62, 0xe9, 0x4e, 0x63, 0xed, 0x57,
+	0xd3, 0x7e, 0xb6, 0x53, 0x50, 0xf0, 0x92, 0x25, 0xfb, 0xc7, 0x80, 0xfd, 0x02, 0x88, 0x5f, 0x82,
+	0x39, 0x59, 0x44, 0xa4, 0x23, 0xff, 0xdf, 0xe0, 0x49, 0xf1, 0x2b, 0x45, 0x39, 0xb1, 0xe5, 0xda,
+	0x03, 0x3b, 0xd0, 0xf8, 0x56, 0x5c, 0x9d, 0x8f, 0xd2, 0xd2, 0x2f, 0x05, 0xfc, 0x08, 0x76, 0xd2,
+	0x68, 0x75, 0xb9, 0xab, 0x13, 0xca, 0x4c, 0xd8, 0x4f, 0xd0, 0xae, 0xb8, 0x00, 0xf7, 0xa0, 0xf9,
+	0x2a, 0xf4, 0xe8, 0x67, 0x3f, 0x24, 0xcf, 0xde, 0xc2, 0x77, 0xa0, 0xcd, 0x29, 0x0a, 0xfc, 0xa9,
+	0x9b, 0x58, 0x0c, 0xe7, 0x52, 0x09, 0x79, 0x39, 0xb0, 0x0d, 0xdc, 0x05, 0xeb, 0x22, 0xa6, 0xe8,
+	0x4c, 0x04, 0x9e, 0x5d, 0x43, 0x1b, 0x76, 0x13, 0xe9, 0x58, 0x88, 0xdb, 0x99, 0x2b, 0x6f, 0xed,
+	0x3a, 0xfb, 0xdb, 0x80, 0x83, 0xd2, 0xed, 0x38, 0xd8, 0x48, 0xf9, 0x71, 0x39, 0x3e, 0x27, 0xfd,
+	0xcd, 0x25, 0x8b, 0x60, 0xbe, 0x74, 0x67, 0x94, 0xe6, 0xaa, 0xcf, 0x09, 0xf6, 0x62, 0xee, 0x7b,
+	0x3a, 0x4f, 0x93, 0xeb, 0x33, 0xbe, 0x07, 0xcd, 0xa1, 0x24, 0x37, 0xa6, 0xc9, 0x8f, 0x2f, 0xf4,
+	0x2c, 0x99, 0x7c, 0x0d, 0x60, 0x0f, 0x2c, 0x2d, 0x24, 0xd5, 0x69, 0xe8, 0x2f, 0xad, 0x64, 0xf6,
+	0x14, 0x5a, 0xb9, 0x6b, 0x75, 0x6a, 0xa1, 0x1b, 0xa9, 0x1b, 0x11, 0xdb, 0x5b, 0x89, 0xb4, 0x4a,
+	0xcb, 0x60, 0x7f, 0x19, 0xb0, 0x93, 0x94, 0xed, 0x01, 0xf3, 0x87, 0x1f, 0x82, 0x79, 0x2a, 0xc5,
+	0x4c, 0x07, 0x5e, 0xdd, 0x0c, 0xad, 0x47, 0x06, 0xb5, 0x89, 0x78, 0x4b, 0xcb, 0x6a, 0x13, 0x51,
+	0x5c, 0x39, 0xb3, 0xbc, 0x72, 0x0c, 0x9a, 0xeb, 0x55, 0x6a, 0xe8, 0xfa, 0x9a, 0xce, 0x44, 0xfa,
+	0x7c, 0x0d, 0xe3, 0x23, 0xd8, 0x1e, 0xc9, 0x05, 0x9f, 0x87, 0xdd, 0x6d, 0xbd, 0x6b, 0xa9, 0xc4,
+	0x3e, 0x03, 0x6b, 0x2c, 0x45, 0x44, 0x32, 0x5e, 0xac, 0xca, 0x6d, 0xe4, 0xca, 0xdd, 0x81, 0xc6,
+	0xa5, 0x1b, 0xcc, 0xb3, 0x1e, 0x2c, 0x05, 0xf6, 0xfb, 0xaa, 0x16, 0x0a, 0xfb, 0xb0, 0xff, 0x4a,
+	0x91, 0x57, 0xa4, 0x05, 0x8b, 0x17, 0x61, 0x64, 0xb0, 0x7b, 0xf2, 0x26, 0xa2, 0x69, 0x4c, 0xde,
+	0x85, 0xff, 0x2b, 0xe9, 0xbc, 0xeb, 0x7c, 0x03, 0xc3, 0xa7, 0x00, 0x69, 0x3c, 0x3e, 0xa9, 0xae,
+	0xa9, 0xb7, 0xac, 0xe9, 0x64, 0x21, 0xf2, 0x9c, 0x92, 0x3d, 0x5b, 0xae, 0xe5, 0x50, 0xcc, 0xa2,
+	0x80, 0x62, 0xd2, 0x8d, 0x39, 0x82, 0xd6, 0x0f, 0xd2, 0xbf, 0xf6, 0x43, 0x37, 0xe0, 0x74, 0x97,
+	0xd6, 0xdf, 0x72, 0xd2, 0xbe, 0xf1, 0xbc, 0x92, 0x61, 0xc9, 0x5f, 0xb1, 0xdf, 0x00, 0x38, 0x4d,
+	0xc9, 0xff, 0x85, 0x1e, 0xd2, 0xe6, 0x65, 0xfb, 0x6a, 0x6f, 0x6d, 0xdf, 0x11, 0xd8, 0xc3, 0x80,
+	0x5c, 0x99, 0xaf, 0xcf, 0x92, 0x12, 0x4b, 0x38, 0xdb, 0xcd, 0xdd, 0xae, 0xd8, 0x35, 0xb4, 0x47,
+	0xa4, 0x62, 0x29, 0x16, 0xd9, 0x4c, 0x3e, 0x84, 0xfb, 0xf0, 0x13, 0x68, 0xae, 0xec, 0x53, 0x9a,
+	0xaa, 0x8a, 0x6d, 0x6d, 0xc4, 0x5e, 0x03, 0x16, 0x2e, 0x4a, 0x59, 0x32, 0x13, 0xf5, 0x2d, 0xf7,
+	0xb0, 0x64, 0x66, 0x93, 0x4c, 0xca, 0x89, 0x94, 0x42, 0x66, 0x93, 0xa2, 0x05, 0x36, 0xaa, 0x4a,
+	0x22, 0x79, 0x99, 0x76, 0x92, 0xc4, 0x83, 0x38, 0x63, 0xe0, 0xb6, 0x53, 0x0e, 0x81, 0x67, 0x36,
+	0xec, 0x0b, 0xe8, 0x94, 0xb8, 0xe8, 0x21, 0xef, 0xc0, 0xa4, 0xd2, 0x4f, 0x61, 0x27, 0x25, 0x91,
+	0xc4, 0xc3, 0x3c, 0xdb, 0x5a, 0xd1, 0x88, 0xf5, 0x52, 0xc4, 0xf4, 0xc6, 0x57, 0xf1, 0x72, 0x84,
+	0xcf, 0xb6, 0xf8, 0x0a, 0x39, 0xb6, 0x60, 0x7b, 0x19, 0x0e, 0xfb, 0x00, 0x76, 0xc6, 0x7e, 0x78,
+	0x9d, 0x04, 0xd0, 0x85, 0x9d, 0xef, 0x49, 0x29, 0xf7, 0x3a, 0xdb, 0x9a, 0x4c, 0x64, 0xef, 0x67,
+	0x46, 0x2a, 0xd9, 0xab, 0x93, 0xe9, 0x8d, 0xc8, 0xf6, 0x2a, 0x39, 0x1f, 0xf5, 0xa1, 0x3e, 0x91,
+	0x7e, 0x42, 0x31, 0x23, 0x11, 0xc6, 0x43, 0x57, 0x92, 0xbd, 0x85, 0x4d, 0x68, 0x9c, 0xba, 0x81,
+	0x22, 0xdb, 0x40, 0x0b, 0xcc, 0x89, 0x9c, 0x93, 0x5d, 0x1b, 0xfc, 0x5b, 0x4b, 0x08, 0x60, 0x95,
+	0x04, 0xf6, 0xc0, 0x4c, 0x3e, 0x8c, 0x96, 0x93, 0x06, 0xd1, 0xcb, 0x4e, 0x0a, 0xbf, 0x82, 0xfd,
+	0xcd, 0x67, 0x4f, 0x21, 0x3a, 0xa5, 0x3f, 0x0b, 0xbd, 0x32, 0xa6, 0x70, 0x0c, 0x8f, 0xaa, 0x5f,
+	0x4c, 0xec, 0x39, 0xf7, 0x3e, 0xc4, 0xbd, 0xfb, 0x75, 0x0a, 0x9f, 0x81, 0x5d, 0x6c, 0x3d, 0x76,
+	0x9c, 0x8a, 0x91, 0xee, 0x55, 0xa1, 0x0a, 0x9f, 0xc3, 0x41, 0xa9, 0x79, 0xf8, 0x7f, 0xa7, 0x6a,
+	0x10, 0x7a, 0x95, 0xb0, 0xc2, 0xcf, 0x61, 0x6f, 0x63, 0xc5, 0xf1, 0xc0, 0x29, 0x52, 0x46, 0xaf,
+	0x04, 0xa9, 0xe3, 0xc6, 0xeb, 0x7a, 0xe4, 0xcd, 0xaf, 0xb6, 0xf5, 0xff, 0xad, 0x4f, 0xff, 0x0b,
+	0x00, 0x00, 0xff, 0xff, 0x0a, 0xa0, 0x3f, 0xc2, 0x7c, 0x09, 0x00, 0x00,
 }
--- a/replication/logic/pdu/pdu.proto
+++ b/replication/logic/pdu/pdu.proto
@ -25,7 +25,22 @@ message Filesystem {

 message ListFilesystemVersionsReq { string Filesystem = 1; }

-message ListFilesystemVersionsRes { repeated FilesystemVersion Versions = 1; }
+message ListFilesystemVersionsRes {
+  repeated FilesystemVersion Versions = 1;
+  repeated SendAbstraction SendAbstractions = 2;
+}
+
+message SendAbstraction {
+  enum SendAbstractionType {
+    Undefined = 0;
+    ReplicationCursorV2 = 1;
+    StepHold = 2;
+    StepBookmark = 3;
+  };
+  SendAbstractionType Type = 1;
+  string JobID = 2;
+  FilesystemVersion Version = 3;
+}

 message FilesystemVersion {
  enum VersionType {
@ -80,9 +95,7 @@ message SendRes {
  repeated Property Properties = 4;
 }

-message SendCompletedReq {
-  SendReq OriginalReq = 2;
-}
+message SendCompletedReq { SendReq OriginalReq = 2; }

 message SendCompletedRes {}

@ -98,7 +111,7 @@ message ReceiveReq {
 message ReceiveRes {}

 message DestroySnapshotsReq {
-  string Filesystem = 1;
+string Filesystem = 1;
  // Path to filesystem, snapshot or bookmark to be destroyed
  repeated FilesystemVersion Snapshots = 2;
 }
--- a/zfs/versions.go
+++ b/zfs/versions.go
@ -115,6 +115,8 @@ func (v FilesystemVersion) RelName() string {
 }
 func (v FilesystemVersion) String() string { return v.RelName() }

+func (v FilesystemVersion) GetCreation() time.Time { return v.Creation }
+
 // Only takes into account those attributes of FilesystemVersion that
 // are immutable over time in ZFS.
 func FilesystemVersionEqualIdentity(a, b FilesystemVersion) bool {
--- a/zfs/zfs.go
+++ b/zfs/zfs.go
@ -1500,6 +1500,30 @@ func tryParseDestroySnapshotsError(arg string, stderr []byte) *DestroySnapshotsE
 	}
 }

+type ErrDestroySnapshotDatasetIsBusy struct {
+	*DestroySnapshotsError
+	Name string
+}
+
+var _ error = (*ErrDestroySnapshotDatasetIsBusy)(nil)
+
+func tryErrDestroySnapshotDatasetIsBusy(arg string, stderr []byte) *ErrDestroySnapshotDatasetIsBusy {
+	dsne := tryParseDestroySnapshotsError(arg, stderr)
+	if dsne == nil {
+		return nil
+	}
+	if len(dsne.Reason) != 1 {
+		return nil
+	}
+	if dsne.Reason[0] == "dataset is busy" {
+		return &ErrDestroySnapshotDatasetIsBusy{
+			DestroySnapshotsError: dsne,
+			Name:                  dsne.Undestroyable[0],
+		}
+	}
+	return nil
+}
+
 func ZFSDestroy(ctx context.Context, arg string) (err error) {

 	var dstype, filesystem string
@ -1533,6 +1557,8 @@ func ZFSDestroy(ctx context.Context, arg string) (err error) {
 			err = &DatasetDoesNotExist{arg}
 		} else if dsNotExistErr := tryDatasetDoesNotExist(filesystem, stdio); dsNotExistErr != nil {
 			err = dsNotExistErr
+		} else if dsBusy := tryErrDestroySnapshotDatasetIsBusy(arg, stdio); dsBusy != nil {
+			err = dsBusy
 		} else if dserr := tryParseDestroySnapshotsError(arg, stdio); dserr != nil {
 			err = dserr
 		}