I recently rebuilt my lab NAS hosts with Ubuntu 16.04 and used ZFS for
the storage pools (once again). In doing it this time around I wanted to
get a good method of leveraging ZFS snapshots and replicating them for
my backups. I ended up coming up with the following script that has been
working out quite well so far. As usual, I figured it might be
worthwhile to share this for others to leverage as well.
#!/usr/bin/env bash
# ZFS Backups to remote server using replication
# Larry Smith Jr.
# @mrlesmithjr
# http://everythingshouldbevirtual.com
# Turn on verbose execution
set -x
# Source definitions
# ------------------
# Source ZFS Pool
SRCPOOL="TANK"
# Define ZFS dataset(s) to backup
# BACKUP=("Shares" "Data")
BACKUP=("Shares")
# Define snapshot name to use for most recent snapshot
CURRENTSNAP="replicate"
# Define snapshot name to use as previous snapshot
OLDSNAP="replicated"
# Define ZFS send options on source
SNDOPTS="-R -i"
# ------------------
# Destination server definitions
# ------------------------------
# Destination Pool on remote server
DSTPOOL="TANK"
# Define remote server to backup to
BACKUPSRV="nas02"
# Define dataset compression
COMPRESSION="lz4"
# Define main ZFS dataset to use as backup destination
DESTMAINDS="$DSTPOOL/Backups"
# Define dataset(s) on remote server to create under DESTMAINDS
# DESTDS=("Shares" "Data")
DESTDS=("Shares")
# Define remote server ZFS receive options
RCVOPTS="-vF"
# ------------------------------
# Ensure ZFS main dataset(s) exist on remote server
ssh $BACKUPSRV sudo zfs list | grep $DESTMAINDS
RC=$?
if [ $RC != 0 ]; then
ssh $BACKUPSRV sudo zfs create -o compression=$COMPRESSION $DESTMAINDS
fi
# Ensure ZFS dataset(s) under DESTMAINDS exist on remote server
for DST in "${DESTDS[@]}"
do
ssh $BACKUPSRV sudo zfs list | grep $DESTMAINDS/$DST
RC=$?
# Create ZFS dataset(s) if they are missing on remote server
if [ $RC != 0 ]; then
ssh $BACKUPSRV sudo zfs create -o compression=$COMPRESSION $DESTMAINDS/$DST
fi
done
# Execute backup
# Loop through backup dataset(s) to backup
for BACKUPFS in "${BACKUP[@]}"
do
# Check if destination backup dataset(s) exist
ssh $BACKUPSRV sudo zfs list | grep $DESTMAINDS/$BACKUPFS
RC=$?
if [ $RC != 0 ]; then
# Send first initial replication of backup dataset(s) if they do not exist
sudo zfs snapshot -r $SRCPOOL/$BACKUPFS@$CURRENTSNAP
sudo zfs send -R $SRCPOOL/$BACKUPFS@$CURRENTSNAP | ssh $BACKUPSRV sudo zfs receive -F $DESTMAINDS/$BACKUPFS
else
# Destroy already replicated snapshot(s)
ssh $BACKUPSRV sudo zfs destroy -r $DESTMAINDS/$BACKUPFS@$OLDSNAP.7
sudo zfs destroy -r $SRCPOOL/$BACKUPFS@$OLDSNAP.7
# Rename previous replicated snapshot(s) on remote server...Keeping 7 previous replicated snapshot(s)
ssh $BACKUPSRV sudo zfs rename -r $DESTMAINDS/$BACKUPFS@$OLDSNAP.6 @$OLDSNAP.7
ssh $BACKUPSRV sudo zfs rename -r $DESTMAINDS/$BACKUPFS@$OLDSNAP.5 @$OLDSNAP.6
ssh $BACKUPSRV sudo zfs rename -r $DESTMAINDS/$BACKUPFS@$OLDSNAP.4 @$OLDSNAP.5
ssh $BACKUPSRV sudo zfs rename -r $DESTMAINDS/$BACKUPFS@$OLDSNAP.3 @$OLDSNAP.4
ssh $BACKUPSRV sudo zfs rename -r $DESTMAINDS/$BACKUPFS@$OLDSNAP.2 @$OLDSNAP.3
ssh $BACKUPSRV sudo zfs rename -r $DESTMAINDS/$BACKUPFS@$OLDSNAP.1 @$OLDSNAP.2
ssh $BACKUPSRV sudo zfs rename -r $DESTMAINDS/$BACKUPFS@$OLDSNAP @$OLDSNAP.1
ssh $BACKUPSRV sudo zfs rename -r $DESTMAINDS/$BACKUPFS@$CURRENTSNAP @$OLDSNAP
# Rename previous replicated snapshot(s) locally...Keeping 7 previous replicated snapshot(s)
sudo zfs rename -r $SRCPOOL/$BACKUPFS@$OLDSNAP.6 @$OLDSNAP.7
sudo zfs rename -r $SRCPOOL/$BACKUPFS@$OLDSNAP.5 @$OLDSNAP.6
sudo zfs rename -r $SRCPOOL/$BACKUPFS@$OLDSNAP.4 @$OLDSNAP.5
sudo zfs rename -r $SRCPOOL/$BACKUPFS@$OLDSNAP.3 @$OLDSNAP.4
sudo zfs rename -r $SRCPOOL/$BACKUPFS@$OLDSNAP.2 @$OLDSNAP.3
sudo zfs rename -r $SRCPOOL/$BACKUPFS@$OLDSNAP.1 @$OLDSNAP.2
sudo zfs rename -r $SRCPOOL/$BACKUPFS@$OLDSNAP @$OLDSNAP.1
sudo zfs rename -r $SRCPOOL/$BACKUPFS@$CURRENTSNAP @$OLDSNAP
# Create new current snapshot(s)
sudo zfs snapshot -r $SRCPOOL/$BACKUPFS@$CURRENTSNAP
# Replicate incremental snapshot(s) to remote server
sudo zfs send $SNDOPTS $SRCPOOL/$BACKUPFS@$OLDSNAP $SRCPOOL/$BACKUPFS@$CURRENTSNAP | ssh $BACKUPSRV sudo zfs receive $RCVOPTS $DESTMAINDS/$BACKUPFS
fi
# ssh $BACKUPSRV sudo zfs set mountpoint=/$DESTMAINDS/$BACKUPFS $DESTMAINDS/$BACKUPFS
done
Enjoy!
ZFS
Storage
January 7, 2017
