Updated Debugging (markdown)

Debugging.md

@@ -9,7 +9,37 @@
 * Reduce network bandwidth between the VMs:
    *  Use https://github.com/thombashi/tcconfig instead of Linux `tc`
       * `tcset eth0 --rate 100Mbps --direction incoming --src-network 192.168.124.233/32 --overwrite`
+* Fake zfs errors
+   * Create a wrapper shell script and add its director to the zrepl daemon's `PATH`
+   * Example Script: <details>
+      ```
+      root@zrepl-dev-debian-2:[~]: cat mockpath/zfs
+      #!/usr/bin/env bash
+      set -eu
+      args=("$@")
       
+      ZREPL_MOCK_ZFS_PATH=/usr/local/sbin/zfs
+          
+      
+      #if echo "${args[@]}" | egrep 'list.*snapshot' > /dev/null; then
+      #    echo "sleeping ${args[@]}" >> /tmp/mocklog
+      #    sleep 700
+      #fi
+      if echo "${args[@]}" | egrep 'recv -s' 2>&1 >/dev/null; then
+          echo foo
+          echo bar 1>&2
+          sleep 10
+          dd bs=1M count=1
+          exit 23
+          #echo "unenced is blocked to be received by this mock" 1>&2
+          #exit 23
+          sleep 1
+      fi
+      
+      
+      exec "$ZREPL_MOCK_ZFS_PATH" "${args[@]}"
+      ```
+      </details>
 
 ## Memory Leaks & Goroutine Leaks