zfs backup script

backup_zfs.sh

#!/bin/sh

set -e

# Used in ssh command, example user@host -p 2222
REMOTE_HOST="diophante"

# Source zfs pool
POOL_SRC="tank"

# zfs sets to backup (relative to POOL_SRC)
SETS="usr/local/vmail usr/local/data usr/local/pgsql/backups usr/home usr/local/git var/backups"

# Destination pool
POOL_DST="tank/backup/${REMOTE_HOST}"

# We use ssh connection sharing
SSH_ARGS="-o ControlPath=~/.ssh/%r@%h:%p"

# zfs snapshot prefix => tank/foo@bck-2011-05-25
PREFIX="bck-"

# Remote zfs command
REMOTE_ZFS="ssh ${SSH_ARGS} ${REMOTE_HOST} sudo zfs"

# Local zfs command
LOCAL_ZFS="sudo zfs"


# Launch master ssh for sharing connections
ssh -MNn ${SSH_ARGS} ${REMOTE_HOST} &
ssh_master_pid=$!

for zfs_set in ${SETS}
do
	# Test if destination exist
	${LOCAL_ZFS} list -H ${POOL_DST}/${zfs_set} >/dev/null

	date_suffix="${PREFIX}`date +%F`"
	snap="${POOL_SRC}/${zfs_set}@${date_suffix}"
	old_snap=`${REMOTE_ZFS} list -Ht snapshot 2>/dev/null | grep "^${POOL_SRC}/${zfs_set}@${PREFIX}" 2>/dev/null| awk -F' ' '{ print $1 }' 2>/dev/null`
	if [ "${old_snap}" ]
	then

		if [ "${old_snap}" != "`echo ${old_snap} | head -n 1`" ]
		then
			echo "[!] Multiple zfs snapshot found: ${old_snap}"
			echo "[!] Consider changing PREFIX or fix the issue yourself"
			continue
		fi

		if [ "${old_snap}" = "${snap}" ]
		then
			echo "[!] ${snap} exists"
			continue
		fi
	fi
	echo ${REMOTE_ZFS} snapshot "${snap}"
	${REMOTE_ZFS} snapshot "${snap}"

	if [ "${old_snap}" ]
	then
		extra_args="-i ${old_snap}"
	else
		extra_args=""
	fi

	echo ${REMOTE_ZFS} send $extra_args "${snap}" '|' ${LOCAL_ZFS} recv -F "${POOL_DST}/${zfs_set}"
	${REMOTE_ZFS} send $extra_args "${snap}" | ${LOCAL_ZFS} recv -F "${POOL_DST}/${zfs_set}"

	if [ "${old_snap}" ]
	then
		echo ${REMOTE_ZFS} destroy "${old_snap}"
		${REMOTE_ZFS} destroy "${old_snap}"
	fi
done

kill $ssh_master_pid