From 8d48656d2feffc292d64efc4054e374a5ca3ba47 Mon Sep 17 00:00:00 2001
From: Gardouille <gardouille@gmail.com>
Date: Tue, 18 Nov 2014 16:02:20 +0100
Subject: [PATCH] Small script to take ZFS snapshot periodically and send it to
 a remote host. Will be replace by zfSnap soon (many pull request to add a
 send option), maybe in v2.1.

---
 snapsend.sh | 172 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 172 insertions(+)
 create mode 100755 snapsend.sh

diff --git a/snapsend.sh b/snapsend.sh
new file mode 100755
index 0000000..f3f7418
--- /dev/null
+++ b/snapsend.sh
@@ -0,0 +1,172 @@
+#!/bin/sh
+#
+# 2014/11/14 - Initial script creation
+#
+# Based on snapxfer script by pds from zpool.org
+# https://zpool.org/zfs-snapshots-and-remote-replication/
+#
+# Also main use zfSnap (https://github.com/zfsnap/zfsnap/wiki/zfSnap)
+# Must take the 1.x version (tree legacy). Too many changes in the 2.0.0 beta.
+
+# Local ZFS filesystems that will have a snapshot
+DATASETS="datastore/vm"
+
+# Destination host for snapshot replication
+# The user must have enought rights to use `zfs command`
+DHOST="root@192.168.42.52"
+
+# Output logfile
+LOGFILE="/var/log/snapsend/snapsend.log"
+
+# Tools that help implement snapshot logic (and transfer soon according the pull-requests)
+ZSNAP="/usr/local/bin/zfSnap.sh"
+
+# Administrator's email
+MAILADMIN="admin1@localhost,admin2@localhost"
+
+# List of all ZFS snapshot
+SNAP_LIST=''
+REMOTE_SNAP_LIST=''
+
+# The prefix to add to the previous snapshot's name which is now useless
+PREFIXSNAP='done_'
+
+######################################################################
+# Functions #
+######################################################################
+
+# Returns 0 if snapshot exists
+SnapExists() {
+  SNAP_LIST="${SNAP_LIST:-`zfs list -H -o name -t snapshot`}"
+  local i
+  for i in $SNAP_LIST; do
+    [ "$1" = "$i" ] && return 0
+  done
+  return 1
+}
+
+# Returns 0 if snapshot exists on the remote host
+RemoteSnapExist() {
+  REMOTE_SNAP_LIST="${REMOTE_SNAP_LIST:-`ssh ${1} zfs list -H -o name -t snapshot`}"
+  local i
+  for i in $REMOTE_SNAP_LIST; do
+    [ "$2" = "$i" ] && return 0
+  done
+  return 1
+}
+
+######################################################################
+# Main logic #
+######################################################################
+
+interval=$1
+
+usage()
+{
+  if [ "X${interval}" = "X" ]; then
+    printf 'Usage: %s (async|hourly|daily|weekly|purge)\n' $(basename $0)
+    printf '\n'
+    printf '* Asynchronous DR snapshots are kept for 1 hour\n'
+    printf '* Hourly snapshots are kept for 1 day\n'
+    printf '* Daily snapshots are kept for one week\n'
+    printf '* Weekly snapshots are kept for one month\n'
+    printf '\n'
+
+    exit 1
+  fi
+}
+
+if [ ! -f "${LOGFILE}" ]; then
+  mkdir -p $(dirname ${LOGFILE})
+  touch "${LOGFILE}"
+fi
+
+case "${interval}" in
+  'async' )
+    for dset in $DATASETS
+    do
+      # Take snapshots for asynchronouss DR purposes
+      $ZSNAP -v -s -S -a 1h $dset >> $LOGFILE
+
+      # Get the last snapshot name on localhost
+      LOCALSNAP=$(zfs list -H -o name -t snapshot -r ${dset} | tail -n1 | cut -d@ -f2)
+      #printf 'Local snapshot: %s\n' ${LOCALSNAP}
+
+      # Get the last snapshot name on remote host $DHOST
+      DHOSTSNAP=$(ssh ${DHOST} zfs list -H -o name -t snapshot -r ${dset} | tail -n1 | cut -d@ -f2)
+      #printf 'Remote snapshot: %s\n' ${DHOSTSNAP}
+
+      # Test if $DHOSTSNAP exist on the local system
+      # Recompose the full snapshot name with $dset@$DHOSTSNAP
+      if SnapExists "${dset}@${DHOSTSNAP}"; then
+        #printf '%s exist on the local system\n' ${DHOSTSNAP}
+        printf '%s@%s will be send to %s to replace the old snapshot: %s' ${dset} ${LOCALSNAP} ${DHOST} ${DHOSTSNAP} >> $LOGFILE
+
+        # Send the snapshot the remote host
+        # zfs send -I datastore/vm@2014-11-17_11.26.22--1h datastore/vm@2014-11-18_14.19.10--1h | ssh nec02.ipr.univ-rennes1.fr zfs recv datastore/vm
+        zfs send -I "${DHOSTSNAP}" "${dset}@${LOCALSNAP}" | ssh "${DHOST}" zfs recv "${dset}"
+        printf ' ... done\n' >> $LOGFILE
+      else
+        # Mail admin
+        printf 'ERROR snapshot %s does not exist on the local system\n' ${DHOSTSNAP} | mail ${MAILADMIN} -s 'snapsend_error'
+        printf 'ERROR snapshot %s for %s does not exist on the local system\n' ${DHOSTSNAP} ${dset} >> $LOGFILE
+      fi
+
+      # Test if the snapshot was successfully receive on the remote host
+      if RemoteSnapExist "${DHOST}"  "${dset}@${LOCALSNAP}"; then
+        printf 'SUCCESS: the snapshot %s for %s exist on the remote host (%s)\n' ${LOCALSNAP} ${dset} ${DHOST} >> $LOGFILE
+
+        # Rename the useless snapshot for the next purge
+        zfs rename ${dset}@${DHOSTSNAP} ${dset}@${PREFIXSNAP}${DHOSTSNAP}
+      else
+        # Mail admin
+        printf 'ERROR snapshot %s for %s does not exist on the remote host (%s)\n' ${LOCALSNAP} ${dset} ${DHOST} | mail ${MAILADMIN} -s 'snapsend_error'
+        printf 'ERROR snapshot %s for %s does not exist on the remote host (%s)\n' ${LOCALSNAP} ${dset} ${DHOST} >> $LOGFILE
+      fi
+    done
+
+    printf '\n' >> $LOGFILE
+    ;;
+
+  'hourly' )
+    # take snapshots, keep for one day
+    for dset in $DATASETS
+    do
+      $ZSNAP -v -s -S -a 1d $dset >> $LOGFILE
+    done
+    printf '\n' >> $LOGFILE
+    ;;
+
+  'daily' )
+    # take snapshots, keep for one week
+    for dset in $DATASETS
+    do
+      $ZSNAP -v -s -S -a 1w $dset >> $LOGFILE
+    done
+
+    # Purge snapshots according to TTL
+    $ZSNAP -v -s -S -d -p ${PREFIXSNAP} >> $LOGFILE
+    printf '\n' >> $LOGFILE
+    ;;
+
+  'weekly' )
+    # take snapshots, keep for one month
+    for dset in $DATASETS
+    do
+      $ZSNAP -v -s -S -a 1m $dset >> $LOGFILE
+    done
+    printf '\n' >> $LOGFILE
+    ;;
+
+  'purge' )
+    # purge snapshots according to TTL
+    $ZSNAP -v -s -S -d
+    ;;
+
+  * )
+    usage
+    ;;
+
+esac
+
+exit 0