Automatically trigger zfs-autobackup when an (external) backup disk is attached using the udev-trigger-zfs-autobackup daemon. Useful to store encrypted backups offline, on disks you can easily swap and store offsite. Works with USB, eSATA and disks in hotswap trays.
Specifically made for and tested on TrueNAS SCALE, but made in a generic way so it should work on other hosts too. Please report if you try it on another host, like Proxmox or Ubuntu.
Monitors udev events to detect when new disks are attached. If the attached disk has a ZFS pool on it, and the zpool name matches one of the names set in the config file, then it will be used as a backup disk. All datasets where the ZFS property autobackup matches the zpool name of the backup disk will be automatically backed up using zfs-autobackup.
Usage: trigger.sh [-h] [-v] [--install]
Daemon to trigger zfs-autobackup when attaching backup disk.
1. Manually create (encrypted) ZFS pool(s) on removable disk(s).
2. Manually edit config to specify the names of your backup pool(s) and the encryption passphrase.
3. Manually schedule trigger.sh to run at system startup. On TrueNAS SCALE: System Settings -> Advanced -> Init/Shutdown Scripts -> Add -> Description: trigger-zfs-autobackup; Type: Script; Script: /path/to/trigger.sh; When: Post Init -> Save
4. Manually insert backup disk whenever you want to make a backup.
5. Automatic backup is triggered and sends email on completion.
Available options:
-h, --help Print this help and exit
-v, --verbose Print script debug info
-i, --install Install dependencies
For security reasons, ensure only root can modify the udev-trigger-zfs-autobackup files. The scripts will be automatically executed with root privileges, so you don't want anyone to modify what they do.
If udev-trigger-zfs-autobackup is already installed, then temporarily disable the trigger by editing config (set enabled to false).
Execute the following commands to prepare a backup disk to use with udev-trigger-zfs-autobackup. Please read the commands (and comments!) carefully before executing them. You have to change several values.
# Carefully determine which disk to format as backup disk!
# All data on it will be lost permanently!
DISK=/dev/disk/by-id/usb-SanDisk_Ultra_Fit_XXXXXXXXXXXXXXXXXXXX-0:0
# Decide on a name for your backup pool
POOL=offsite1
wipefs -a $DISK
sgdisk --zap-all $DISK
sgdisk --new=1:0:0 --typecode=1:BF00 $DISK
# Use failmode=continue to prevent system from hanging on unclean device disconnect
# If you don't want to use encryption, then remove the encryption and keylocation options
zpool create \
-O encryption=aes-256-gcm \
-O keylocation=prompt -O keyformat=passphrase \
-O acltype=posixacl \
-O compression=zstd \
-O atime=off \
-O aclmode=discard \
-O aclinherit=passthrough \
-o failmode=continue \
-R /mnt \
$POOL $DISK
# If using encryption, you'll be asked to type your passphrase two times. Don't forget to manually edit the config file and put the passphrase in there when installing udev-trigger-zfs-autobackup
# Export the pool and manually disconnect the disk
zpool export $POOL
# Manually set autobackup:offsite1 on the datasets you want to backup (exchange offsite1 for the value chosen voor POOL above)Don't forget to re-enable the backups by editing config in case you had installed udev-trigger-zfs-autobackup before.
Download this repository on the system you want to backup. Then install the dependencies by calling trigger.sh --install from the shell. This will install the dependencies locally using a Python virtual environment. The installation makes no modifications to the system outside of its installation directory. This is to ensure udev-trigger-zfs-autobackup will survive updates of TrueNAS SCALE (as long as you store it on one of your data pools, and not on the disks where the TrueNAS base system is installed).
You need to edit the config file. Specify the names of your backup pools via config values starting with backup_pool_. Also specify your encryption passphrase. You need to use the same passphrase for all of your backup pools.
The trigger.sh script needs to run on system startup. You need to manually this, for example using cron or systemd. On TrueNAS SCALE you can schedule the script via the web interface: System Settings -> Advanced -> Init/Shutdown Scripts -> Add -> Description: trigger-zfs-autobackup; Type: Script; Script: /path/to/trigger.sh; When: Post Init -> Save.
Add the autobackup property to the datasets you want to backup automatically to a backup pool. For example, to automatically backup the dataset data to backup pool offsite1 run: zfs set autobackup:offsite1=true data. You can exclude descending datasets. For example excluding ix-applications would work like this: zfs set autobackup:offsite1=false data/ix-applications.
Connect your backup disk to trigger the automatic backup. You'll hear a beep confirming the start of the backup and you'll receive an email with the summary of the backup job.
To (temporarily) disable executing automatic backups, set enabled=false in config.
A ZFS snapshot will be made before each backup. Snapshots will be kept according to the default schedule from the zfs-autobackup Thinner.
[Source] Keep the last 10 snapshots.
[Source] Keep every 1 day, delete after 1 week.
[Source] Keep every 1 week, delete after 1 month.
[Source] Keep every 1 month, delete after 1 year.
I recommend to create a separate cronjob on the host, to frequently take snapshots (not just when you plugin your backup disk). These snapshots will then also be transferred to the backup disk once you connect it. Your backup will contain more snapshots and you'll have more 'versions' to recover from.
The command to schedule via cron could look something like this: cd /path/to/udev-trigger-zfs-autobackup && . venv/bin/activate && zfs-autobackup offsite1. Don't forget to change the path and replace offsite1 with the autobackup ZFS property you added to your source datasets. Then schedule it to run hourly.
Temporarily disable automatic backups then connect your backup disk. Manually import the pool (offsite1 in this example) with zpool import offsite1 -R /mnt. Unlock the pool with zfs load-key offsite1 and enter the passphrase from your config file. Recursively mount the pool and descendant datasets with zfs list -rH -o name offsite1 | xargs -L 1 zfs mount. You can now cd into it with cd /mnt/offsite1 and list the contents. Snapshots are found in a .zfs subdirectory inside each dataset. E.g. /mnt/offsite1/.zfs/snapshot. You could also call zfs mount -a to mount the pool and descending datasets, but it will mount all available ZFS file systems (not just the ones on your backup disk) so it may have side effects. There's currently no zfs command to recursively mount a specific dataset.
I recommend reading the zfs-autobackup documentation if you want to use udev-trigger-zfs-autobackup.