Merge branch 'topic/hanoi' of git://github.com/rdparker/zfs-auto-snapshot into hanoi

Fix SNAPNAME to contain the DATE if label is empty

Makefile

@@ -2,6 +2,16 @@ all:
 
 install:
 	install -d $(DESTDIR)$(PREFIX)/etc/cron.d
-	install etc/zfs-auto-snapshot.cron $(DESTDIR)$(PREFIX)/etc/cron.d/zfs-auto-snapshot
+	install -d $(DESTDIR)$(PREFIX)/etc/cron.daily
+	install -d $(DESTDIR)$(PREFIX)/etc/cron.hourly
+	install -d $(DESTDIR)$(PREFIX)/etc/cron.weekly
+	install -d $(DESTDIR)$(PREFIX)/etc/cron.monthly
+	install etc/zfs-auto-snapshot.cron.frequent $(DESTDIR)$(PREFIX)/etc/cron.d/zfs-auto-snapshot
+	install etc/zfs-auto-snapshot.cron.hourly   $(DESTDIR)$(PREFIX)/etc/cron.hourly/zfs-auto-snapshot
+	install etc/zfs-auto-snapshot.cron.daily    $(DESTDIR)$(PREFIX)/etc/cron.daily/zfs-auto-snapshot
+	install etc/zfs-auto-snapshot.cron.weekly   $(DESTDIR)$(PREFIX)/etc/cron.weekly/zfs-auto-snapshot
+	install etc/zfs-auto-snapshot.cron.monthly  $(DESTDIR)$(PREFIX)/etc/cron.monthly/zfs-auto-snapshot
+	install -d $(DESTDIR)$(PREFIX)/share/man/man8
+	install src/zfs-auto-snapshot.8 $(DESTDIR)$(PREFIX)/share/man/man8/zfs-auto-snapshot.8
 	install -d $(DESTDIR)$(PREFIX)/sbin
 	install src/zfs-auto-snapshot.sh $(DESTDIR)$(PREFIX)/sbin/zfs-auto-snapshot

README

@@ -1,4 +1,12 @@
-An alternative implementation of the zfs-auto-snapshot service for Linux.
+zfs-auto-snapshot:
+
+An alternative implementation of the zfs-auto-snapshot service for Linux
+that is compatible with zfs-linux and zfs-fuse.
+
+Automatically create, rotate, and destroy periodic ZFS snapshots. This is
+the utility that creates the @zfs-auto-snap_frequent, @zfs-auto-snap_hourly,
+@zfs-auto-snap_daily, @zfs-auto-snap_weekly, and @zfs-auto-snap_monthly
+snapshots if it is installed.
 
 This program is a posixly correct bourne shell script.  It depends only on
 the zfs utilities and cron, and can run in the dash shell.

etc/zfs-auto-snapshot.cron

@@ -1,7 +0,0 @@
-PATH="/usr/bin:/bin:/usr/sbin:/sbin"
-
-*/15 * * * * root zfs-auto-snapshot -q -g --label=frequent --keep=4  //
-@hourly      root zfs-auto-snapshot -q -g --label=hourly   --keep=24 //
-@daily       root zfs-auto-snapshot -q -g --label=daily    --keep=31 //
-@weekly      root zfs-auto-snapshot -q -g --label=weekly   --keep=4  //
-@monthly     root zfs-auto-snapshot -q -g --label=monthly  --keep=12 //

etc/zfs-auto-snapshot.cron.daily

@@ -0,0 +1,2 @@
+#!/bin/sh
+exec zfs-auto-snapshot --quiet --syslog --label=daily --keep=31 //

etc/zfs-auto-snapshot.cron.frequent

@@ -0,0 +1,3 @@
+PATH="/usr/bin:/bin:/usr/sbin:/sbin"
+
+*/15 * * * * root zfs-auto-snapshot -q -g --label=frequent --keep=4  //

etc/zfs-auto-snapshot.cron.hourly

@@ -0,0 +1,2 @@
+#!/bin/sh
+exec zfs-auto-snapshot --quiet --syslog --label=hourly --keep=24 //

etc/zfs-auto-snapshot.cron.monthly

@@ -0,0 +1,2 @@
+#!/bin/sh
+exec zfs-auto-snapshot --quiet --syslog --label=monthly --keep=12 //

etc/zfs-auto-snapshot.cron.weekly

@@ -0,0 +1,2 @@
+#!/bin/sh
+exec zfs-auto-snapshot --quiet --syslog --label=weekly --keep=8 //

src/zfs-auto-snapshot.8

@@ -0,0 +1,70 @@
+.TH ZFS-AUTO-SNAPSHOT "8" "June 16, 2013" "zfs-auto-snapshot.sh" "System Administration Commands"
+.SH NAME
+zfs-auto-snapshot \- take regular ZFS snapshots
+.SH SYNOPSIS
+.B zfs-auto-snapshot
+[\fIoptions\fR] [\fI-l label\fR] \fI<'//' | name \fR[\fIname\fR...]\fI>\fR
+.SH DESCRIPTION
+.B zfs-auto-snapshot
+automatically creates, rotates, and destroys snapshots for all your
+ZFS datasets, and is compatible with both zfsonlinux and zfs-fuse.
+.SH OPTIONS
+.TP
+\fB\-\-default\-exclude\fR
+By default \fBzfs-auto-snapshot\fR will snapshot all datasets except
+for those in which the user-property \fBcom.sun:auto-snapshot\fR is
+set to \fBfalse\fR.  This option reverses the behavior and requires
+\fBcom.sun:auto-snapshot\fR to be set to \fBtrue\fR.
+.TP
+\fB\-d\fR, \fB\-\-debug\fR
+Print debugging messages.
+.TP
+\fB\-e\fR, \fB\-\-event\fR=\fIEVENT\fR
+Set the com.sun:auto\-snapshot\-desc property to EVENT.
+.TP
+\fB\-\-fast\fR
+Use a faster zfs list invocation.
+.TP
+\fB\-n\fR, \fB\-\-dry\-run\fR
+Print actions without actually doing anything.
+.TP
+\fB\-s\fR, \fB\-\-skip\-scrub\fR
+Do not snapshot filesystems in scrubbing pools.
+.TP
+\fB\-h\fR, \fB\-\-help\fR
+Print the usage message.
+.TP
+\fB\-k\fR, \fB\-\-keep\fR=\fINUM\fR
+Keep NUM recent snapshots and destroy older snapshots.
+.TP
+\fB\-l\fR, \fB\-\-label\fR=\fILAB\fR
+LAB is usually 'hourly', 'daily', or 'monthly'.
+.TP
+\fB\-p\fR, \fB\-\-prefix\fR=\fIPRE\fR
+PRE is 'zfs\-auto\-snap' by default.
+.TP
+\fB\-q\fR, \fB\-\-quiet\fR
+Suppress warnings and notices at the console.
+.TP
+\fB\-\-send\-full\fR=\fIF\fR
+Send zfs full backup. Unimplemented.
+.TP
+\fB\-\-send\-incr\fR=\fIF\fR
+Send zfs incremental backup. Unimplemented.
+.TP
+\fB\-\-sep\fR=\fICHAR\fR
+Use CHAR to separate date stamps in snapshot names.
+.TP
+\fB\-g\fR, \fB\-\-syslog\fR
+Write messages into the system log.
+.TP
+\fB\-r\fR, \fB\-\-recursive\fR
+Snapshot named filesystem and all descendants.
+.TP
+\fB\-v\fR, \fB\-\-verbose\fR
+Print info messages.
+.TP
+name
+Filesystem and volume names, or '//' for all ZFS datasets.
+.SH SEE ALSO
+.BR zfs (8)

src/zfs-auto-snapshot.sh

@@ -29,6 +29,7 @@ opt_backup_incremental=''
 opt_default_exclude=''
 opt_dry_run=''
 opt_event='-'
+opt_fast_zfs_list=''
 opt_keep=''
 opt_label=''
 opt_prefix='zfs-auto-snap'
@@ -51,12 +52,17 @@ SNAPSHOTS_OLD=''
 print_usage ()
 {
 	echo "Usage: $0 [options] [-l label] <'//' | name [name...]>
-  --default-exclude  Exclude objects if com.sun:auto-snapshot is unset.
+  --default-exclude  Exclude datasets if com.sun:auto-snapshot is unset.
   -d, --debug        Print debugging messages.
   -e, --event=EVENT  Set the com.sun:auto-snapshot-desc property to EVENT.
+      --fast         Use a faster zfs list invocation.
   -n, --dry-run      Print actions without actually doing anything.
   -s, --skip-scrub   Do not snapshot filesystems in scrubbing pools.
   -h, --help         Print this usage message.
+  -H, --hanoi=INT    Use the hanoi rotation scheme.
+		     INT how frequently the hanoi rotation is being run.
+		     It is a number followed by one of w, d, h, m, s for
+		     weeks, days, hours, minutes or seconds.
   -k, --keep=NUM     Keep NUM recent snapshots and destroy older snapshots.
   -l, --label=LAB    LAB is usually 'hourly', 'daily', or 'monthly'.
   -p, --prefix=PRE   PRE is 'zfs-auto-snap' by default.
@@ -67,7 +73,7 @@ print_usage ()
   -g, --syslog       Write messages into the system log.
   -r, --recursive    Snapshot named filesystem and all descendants.
   -v, --verbose      Print info messages.
-      name           Filesystem and volume names, or '//' for all ZFS objects.
+      name           Filesystem and volume names, or '//' for all ZFS datasets.
 " 
 }
 
@@ -138,6 +144,123 @@ do_run () # [argv]
 }
 
 
+do_rotate () # flags, oldglob, target
+{
+	local FLAGS="$1"
+	local GLOB="$2"
+	local TARGET="$3"
+	local KEEP=''
+
+	# global DESTRUCTION_COUNT
+	# global WARNING_COUNT
+	# global SNAPSHOTS_OLD
+
+	# Retain at most $opt_keep number of old snapshots of this filesystem,
+	# including the one that was just recently created.
+	KEEP="$opt_keep"
+
+	# ASSERT: The old snapshot list is sorted by increasing age.
+	for jj in $SNAPSHOTS_OLD
+	do
+		# Check whether this is an old snapshot of the filesystem.
+		if [ -z "${jj#$TARGET@$GLOB}" ]
+		then
+			KEEP=$(( $KEEP - 1 ))
+			if [ "$KEEP" -le '0' ]
+			then
+				if do_run "zfs destroy $FLAGS '$jj'" 
+				then
+					DESTRUCTION_COUNT=$(( $DESTRUCTION_COUNT + 1 ))
+				else
+					WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
+				fi
+			fi
+		fi
+	done
+}
+
+
+compute_hanoi_level() # date
+{
+	local DATE="$1"
+	local EPOCH_TIME=''
+	local HANOI_NUM=''
+	local HANOI_LEVEL='1'
+
+	# The h* is because on Solaris %H%M will have generated 12h34
+	EPOCH_TIME=$(date +%s --date="$(echo $DATE | sed 's/-\(..\)h*\(..\)$/ \1:\2/')")
+	HANOI_NUM=$(($EPOCH_TIME / $opt_hanoi));
+	while test "$HANOI_NUM" -ne "0"
+	do
+		case "${HANOI_NUM}" in
+			(*[13579])
+				break
+				;;
+		esac
+		HANOI_LEVEL=$(($HANOI_LEVEL + 1))
+		HANOI_NUM=$(($HANOI_NUM / 2))
+	done
+	echo $HANOI_LEVEL
+}
+
+
+do_hanoi () # flags, oldglob, target
+{
+	local FLAGS="$1"
+	local GLOB="$2"
+	local TARGET="$3"
+	local KEEP=''
+	local HANOI_LEVEL='0'
+	local SNAP_DATE=''
+	local SNAP_LEVEL=''
+	local POSSIBLY_DESTROY=''
+
+	# global DESTRUCTION_COUNT
+	# global WARNING_COUNT
+	# global SNAPSHOTS_OLD
+
+	HANOI_LEVEL=$(compute_hanoi_level "$DATE")
+
+	# Retain at most $opt_keep number of old snapshots of this filesystem,
+	# including the one that was just recently created.
+	KEEP="$opt_keep"
+
+	# ASSERT: The old snapshot list is sorted by increasing age.
+	for jj in $SNAPSHOTS_OLD
+	do
+		# Check whether this is an old snapshot of the filesystem.
+		if [ -z "${jj#$TARGET@$GLOB}" ]
+		then
+			# If younger snapshot was stored for possible
+			# deletion, delete it.
+			if [ -n "$POSSIBLY_DESTROY" ]
+			then
+				if do_run "zfs destroy $FLAGS '$POSSIBLY_DESTROY'"
+				then
+					DESTRUCTION_COUNT=$(( $DESTRUCTION_COUNT + 1 ))
+				else
+					WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
+				fi
+				POSSIBLY_DESTROY=''
+			fi
+
+			SNAP_DATE=$(echo $jj | sed 's/.*-\(....-..-..-..h*..\)$/\1/')
+			SNAP_LEVEL=$(compute_hanoi_level "$SNAP_DATE")
+			if test "$HANOI_LEVEL" -eq "$SNAP_LEVEL"
+			then
+				# By default the hanoi rotation scheme acts as
+				# though there are an infinite number of
+				# disks.  So instead of immediately destroying
+				# this snapshot, remember it as possibly
+				# needing to be destroyed and only do so if an
+				# older snapshot is found for this set.
+				POSSIBLY_DESTROY="$jj"
+			fi
+		fi
+	done
+}
+
+
 do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 {
 	local PROPS="$1"
@@ -145,12 +268,9 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 	local NAME="$3"
 	local GLOB="$4"
 	local TARGETS="$5"
-	local KEEP=''
 
-	# global DESTRUCTION_COUNT
 	# global SNAPSHOT_COUNT
 	# global WARNING_COUNT
-	# global SNAPSHOTS_OLD
 
 	for ii in $TARGETS
 	do
@@ -162,29 +282,13 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 			continue
 		fi 
 
-		# Retain at most $opt_keep number of old snapshots of this filesystem,
-		# including the one that was just recently created.
-		test -z "$opt_keep" && continue
-		KEEP="$opt_keep"
-
-		# ASSERT: The old snapshot list is sorted by increasing age.
-		for jj in $SNAPSHOTS_OLD
-		do
-			# Check whether this is an old snapshot of the filesystem.
-			if [ -z "${jj#$ii@$GLOB}" ]
-			then
-				KEEP=$(( $KEEP - 1 ))
-				if [ "$KEEP" -le '0' ]
-				then
-					if do_run "zfs destroy $FLAGS '$jj'" 
-					then
-						DESTRUCTION_COUNT=$(( $DESTRUCTION_COUNT + 1 ))
-					else
-						WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
-					fi
-				fi
-			fi
-		done
+		if test -z "$opt_hanoi"
+		then
+			test -z "$opt_keep" && continue
+			do_rotate "$FLAGS" "$GLOB" "$ii"
+		else
+			do_hanoi  "$FLAGS" "$GLOB" "$ii"
+		fi
 	done
 }
 
@@ -193,10 +297,10 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 # {
 
 GETOPT=$(getopt \
-  --longoptions=default-exclude,dry-run,skip-scrub,recursive \
-  --longoptions=event:,keep:,label:,prefix:,sep: \
+  --longoptions=default-exclude,dry-run,fast,skip-scrub,recursive \
+  --longoptions=event:,hanoi:,keep:,label:,prefix:,sep: \
   --longoptions=debug,help,quiet,syslog,verbose \
-  --options=dnshe:l:k:p:rs:qgv \
+  --options=dnshH:e:l:k:p:rs:qgv \
   -- "$@" ) \
   || exit 128
 
@@ -226,6 +330,10 @@ do
 			fi
 			shift 2
 			;;
+		(--fast)
+			opt_fast_zfs_list='1'
+			shift 1
+			;;
 		(-n|--dry-run)
 			opt_dry_run='1'
 			shift 1
@@ -238,6 +346,29 @@ do
 			print_usage
 			exit 0
 			;;
+		(-H|--hanoi)
+			HANOI_OPT="$2"
+			MULT="";
+			INT="";
+			case "$2" in
+				(*[0-9]s) MULT=1 ;;
+				(*[0-9]m) MULT=60 ;;
+				(*[0-9]h) MULT=3600 ;;
+				(*[0-9]d) MULT=86400 ;;
+				(*[0-9]w) MULT=604800 ;;
+				(*)
+					print_log error "Unrecognized interval $2 for the $1 parameter."
+					exit 139
+					;;
+			esac
+			INT=$(echo $2 | sed 's/.$//')
+			if ! test "$INT" -gt '0' 2>/dev/null
+			then
+				print_log error "The $2 parameter must be a positive integer."
+			fi
+			opt_hanoi=$(($INT * $MULT))
+			shift 2
+			;;
 		(-k|--keep)
 			if ! test "$2" -gt '0' 2>/dev/null
 			then
@@ -256,7 +387,7 @@ do
 			while test "${#opt_prefix}" -gt '0'
 			do
 				case $opt_prefix in
-					([![:alnum:]_-.:\ ]*)
+					([![:alnum:]_.:\ -]*)
 						print_log error "The $1 parameter must be alphanumeric."
 						exit 130
 						;;
@@ -278,7 +409,7 @@ do
 			;;
 		(--sep)
 			case "$2" in 
-				([[:alnum:]_-.:\ ])
+				([[:alnum:]_.:\ -])
 					:
 					;;
 				('')
@@ -328,6 +459,11 @@ then
 	exit 134
 fi
 
+if test -n "$opt_hanoi" -a -z "$opt_label"
+then
+	opt_label=hanoi
+fi
+
 # These are the only times that `zpool status` or `zfs list` are invoked, so
 # this program for Linux has a much better runtime complexity than the similar
 # Solaris implementation.
@@ -339,9 +475,14 @@ ZFS_LIST=$(env LC_ALL=C zfs list -H -t filesystem,volume -s name \
   -o name,com.sun:auto-snapshot,com.sun:auto-snapshot:"$opt_label") \
   || { print_log error "zfs list $?: $ZFS_LIST"; exit 136; }
 
-SNAPSHOTS_OLD=$(env LC_ALL=C zfs list -H -t snapshot -S creation -o name) \
-  || { print_log error "zfs list $?: $SNAPSHOTS_OLD"; exit 137; }
-
+if [ -n "$opt_fast_zfs_list" ]
+then
+	SNAPSHOTS_OLD=$(env LC_ALL=C zfs list -H -t snapshot -o name -s name|grep $opt_prefix |awk '{ print substr( $0, length($0) - 14, length($0) ) " " $0}' |sort -r -k1,1 -k2,2|awk '{ print substr( $0, 17, length($0) )}') \
+	  || { print_log error "zfs list $?: $SNAPSHOTS_OLD"; exit 137; }
+else
+	SNAPSHOTS_OLD=$(env LC_ALL=C zfs list -H -t snapshot -S creation -o name) \
+	  || { print_log error "zfs list $?: $SNAPSHOTS_OLD"; exit 137; }
+fi
 
 # Verify that each argument is a filesystem or volume.
 for ii in "$@"
@@ -358,26 +499,26 @@ do
 done
 
 # Get a list of pools that are being scrubbed.
-ZPOOLS_SCRUBBING=$(echo "$ZFS_STATUS" | awk -F ': ' \
+ZPOOLS_SCRUBBING=$(echo "$ZPOOL_STATUS" | awk -F ': ' \
   '$1 ~ /^ *pool$/ { pool = $2 } ; \
    $1 ~ /^ *scan$/ && $2 ~ /scrub in progress/ { print pool }' \
   | sort ) 
 
 # Get a list of pools that cannot do a snapshot.
-ZPOOLS_NOTREADY=$(echo "$ZFS_STATUS" | awk -F ': ' \
+ZPOOLS_NOTREADY=$(echo "$ZPOOL_STATUS" | awk -F ': ' \
   '$1 ~ /^ *pool$/ { pool = $2 } ; \
    $1 ~ /^ *state$/ && $2 !~ /ONLINE|DEGRADED/ { print pool } ' \
   | sort)
 
-# Get a list of objects for which snapshots are explicitly disabled.
+# Get a list of datasets for which snapshots are explicitly disabled.
 NOAUTO=$(echo "$ZFS_LIST" | awk -F '\t' \
   'tolower($2) ~ /false/ || tolower($3) ~ /false/ {print $1}')
 
-# If the --default-exclude flag is set, then exclude all objects that lack
+# If the --default-exclude flag is set, then exclude all datasets that lack
 # an explicit com.sun:auto-snapshot* property. Otherwise, include them.
 if [ -n "$opt_default_exclude" ]
 then
-	# Get a list of objects for which snapshots are explicitly enabled.
+	# Get a list of datasets for which snapshots are explicitly enabled.
 	CANDIDATES=$(echo "$ZFS_LIST" | awk -F '\t' \
 	  'tolower($2) ~ /true/ || tolower($3) ~ /true/ {print $1}')
 else
@@ -386,20 +527,20 @@ else
 	  'tolower($2) !~ /false/ && tolower($3) !~ /false/ {print $1}')
 fi
 
-# Initialize the list of objects that will get a recursive snapshot.
+# Initialize the list of datasets that will get a recursive snapshot.
 TARGETS_RECURSIVE=''
 
-# Initialize the list of objects that will get a non-recursive snapshot.
+# Initialize the list of datasets that will get a non-recursive snapshot.
 TARGETS_REGULAR=''
 
 for ii in $CANDIDATES
 do
-	# Qualify object names so variable globbing works properly.
+	# Qualify dataset names so variable globbing works properly.
 	# Suppose ii=tanker/foo and jj=tank sometime during the loop.
 	# Just testing "$ii" != ${ii#$jj} would incorrectly match.
 	iii="$ii/"
 
-	# Exclude objects that are not named on the command line.
+	# Exclude datasets that are not named on the command line.
 	IN_ARGS='0'
 	for jj in "$@"
 	do
@@ -413,13 +554,13 @@ do
 		continue
 	fi
 
-	# Exclude objects in pools that cannot do a snapshot.
+	# Exclude datasets in pools that cannot do a snapshot.
 	for jj in $ZPOOLS_NOTREADY
 	do
 		# Ibid regarding iii.
 		jjj="$jj/"
 
-		# Check whether the pool name is a prefix of the object name.
+		# Check whether the pool name is a prefix of the dataset name.
 		if [ "$iii" != "${iii#$jjj}" ]
 		then
 			print_log info "Excluding $ii because pool $jj is not ready."
@@ -427,13 +568,13 @@ do
 		fi
 	done
 
-	# Exclude objects in scrubbing pools if the --skip-scrub flag is set.
+	# Exclude datasets in scrubbing pools if the --skip-scrub flag is set.
 	test -n "$opt_skip_scrub" && for jj in $ZPOOLS_SCRUBBING
 	do
 		# Ibid regarding iii.
 		jjj="$jj/"
 
-		# Check whether the pool name is a prefix of the object name.
+		# Check whether the pool name is a prefix of the dataset name.
 		if [ "$iii" != "${iii#$jjj}" ]
 		then
 			print_log info "Excluding $ii because pool $jj is scrubbing."
@@ -446,17 +587,17 @@ do
 		# Ibid regarding iii.
 		jjj="$jj/"
 
-		# The --recusive switch only matters for non-wild arguments.
+		# The --recursive switch only matters for non-wild arguments.
 		if [ -z "$opt_recursive" -a "$1" != '//' ]
 		then
-			# Snapshot this object non-recursively.
+			# Snapshot this dataset non-recursively.
 			print_log debug "Including $ii for regular snapshot."
 			TARGETS_REGULAR="${TARGETS_REGULAR:+$TARGETS_REGULAR	}$ii" # nb: \t
 			continue 2
-		# Check whether the candidate name is a prefix of any excluded object name.
+		# Check whether the candidate name is a prefix of any excluded dataset name.
 		elif [ "$jjj" != "${jjj#$iii}" ]
 		then
-			# Snapshot this object non-recursively.
+			# Snapshot this dataset non-recursively.
 			print_log debug "Including $ii for regular snapshot."
 			TARGETS_REGULAR="${TARGETS_REGULAR:+$TARGETS_REGULAR	}$ii" # nb: \t
 			continue 2
@@ -468,7 +609,7 @@ do
 		# Ibid regarding iii.
 		jjj="$jj/"
 
-		# Check whether any included object is a prefix of the candidate name.
+		# Check whether any included dataset is a prefix of the candidate name.
 		if [ "$iii" != "${iii#$jjj}" ]
 		then
 			print_log debug "Excluding $ii because $jj includes it recursively."
@@ -487,16 +628,21 @@ do
 	TARGETS_RECURSIVE="${TARGETS_RECURSIVE:+$TARGETS_RECURSIVE	}$ii" # nb: \t
 done
 
+# ISO style date; fifteen characters: YYYY-MM-DD-HHMM
+# On Solaris %H%M expands to 12h34.
+DATE=$(date --utc +%F-%H%M)
+
+if test -n "$opt_hanoi" -a "$opt_event" = "-"
+then
+	opt_event=hanoi-$HANOI_OPT-level-$(compute_hanoi_level $DATE)
+fi
+
 # Linux lacks SMF and the notion of an FMRI event, but always set this property
 # because the SUNW program does. The dash character is the default.
 SNAPPROP="-o com.sun:auto-snapshot-desc='$opt_event'"
 
-# ISO style date; fifteen characters: YYYY-MM-DD-HHMM
-# On Solaris %H%M expands to 12h34.
-DATE=$(date +%F-%H%M)
-
 # The snapshot name after the @ symbol.
-SNAPNAME="$opt_prefix${opt_label:+$opt_sep$opt_label-$DATE}"
+SNAPNAME="$opt_prefix${opt_label:+$opt_sep$opt_label}-$DATE"
 
 # The expression for matching old snapshots.  -YYYY-MM-DD-HHMM
 SNAPGLOB="$opt_prefix${opt_label:+?$opt_label}????????????????"