[Useful script, maybe?] Script to backup FreeNAS jail to gzip compressed file

[m0nkey_]

This doesn't come up very often, but it was something I needed. I wanted to backup my jails to an external backup source. Now, my target doesn't support ZFS, if it did, this would be a non-issue. So, I developed a little script that will automate the backups of jails to compressed files.

So, without further a do, here's the script:

Code:

#!/bin/sh

JAIL_LIST="/mnt/tank/opt/jail-list.txt"         # jail list file
JAIL_POOL="bucket"                              # pool containing jails
JAIL_PATH="jails"                               # jails dataset
JAIL_DATE=`date +%Y%m%d`                        # todays date (YYYYMMDD)
JAIL_DEST="/mnt/tank/opt/jailbackup"            # backup destination

NUM_OF_BACKUPS="1"                              # Keep number of backups

# jail-list.txt should contain the list of jails you want to backup, for example:
#
# plex
# znc
# owncloud

tabs 4

echo "Start backup of jails"

while read JAIL_NAME; do

        printf '\t%s' "${JAIL_NAME}"

        JAIL_SNAP="${JAIL_POOL}/${JAIL_PATH}/${JAIL_NAME}@backup-${JAIL_DATE}"
        JAIL_GZIP="${JAIL_DEST}/${JAIL_NAME}-${JAIL_DATE}.gz"

        zfs snapshot ${JAIL_SNAP}
        zfs send ${JAIL_SNAP} | gzip > ${JAIL_GZIP}

        JAIL_SIZE=`stat -f%z ${JAIL_GZIP}`

        printf ' (%s bytes)\n' "${JAIL_SIZE}"

        zfs destroy ${JAIL_SNAP}

        JAIL_FILE=`ls -b ${JAIL_DEST}/${JAIL_NAME}-*.gz | sort -r`

        COUNT=0
        for FILE in ${JAIL_FILE}; do
                COUNT=`expr ${COUNT} + 1`
                if [ ${COUNT} -gt ${NUM_OF_BACKUPS} ]; then
                        rm -f ${FILE}
                fi
        done

done < ${JAIL_LIST}

echo "Backup complete"

### To restore a gzip'd jail:
### zfs receive pool/jails/jailname < gzip -c jailname.gz

Great, thanks @m0nkey_! Now what do I do? Well my friend, that's up to you. I plan to run this script about once every week, however I feel that might still be too often and reduce it down to once a fortnight or a month.

Where do I put the file? That's entirely up to you. I have a dataset known as 'opt' on my main pool where I usually keep scripts, configuration backups, etc. I also write my jail backups to this dataset too, since it's a dataset I backup on a regular basis.

How do I define what jails are backed up? You will need to create yourself a plain text file, doesn't matter what it's called, listing all your jails. For example; I have three jails: plex, unifi and znc. So I have a jail-list.txt with the contents:

Code:

plex
unifi
znc

My environment isn't the same as yours! What do I need to modify to make it work? You will need to modify various parameters to make it work in your environment. You need to modify JAIL_LIST, JAIL_POOL, JAIL_PATH and JAIL_DEST.

How do I schedule this fantastic script of yours? Well, that can be explained by the wonderful FreeNAS documentation. You can read up about 'Tasks' or cron jobs here: http://doc.freenas.org/9.3/freenas_tasks.html#cron-jobs

How do I restore a jail from a file? I've not had to do this yet, but I imagine this would work. You'd need to test it!

Code:

zfs receive pool/jails/jailname < gzip -c jailname.gz

How do I get help for this script? Reply to this post, I might answer. Or you can find me on IRC in #freenas on Freenode.

YOUR SCRIPT F**KED UP! SOMETHING BROKE! FIX IT! FIX IT! Sorry, but this script is provided as-is without warranty. You should really know not to run un-tested 3rd party code in production. Always test in a virtual machine or something prior. Don't do what I do, wrote and tested this on a live box.