simple-zfs-repl - a simple ZFS replication tool in about 100 lines dash script

Run

Run ./simple-zfs-repl -h for help, it's REALLY™️ simple.

Notice the PREFIX option must be unique, it's used to mark replication position for a target and also used in lock file name.

You may put it into cron job or write a shell loop in a Systemd service.

Why yet another ZFS repl?

There are so many ZFS replication tools, but I'm not satisfied with them:

1. Written in Perl/Python/Go that are not so easy to understand
2. Too many lines to easily understand
3. Some create inconsistent snapshots across ZFS filesystem hierarchy, they should use zfs snapshot -r
4. Some try to manage snapshot retention, I think that is already resolved well by zfs-auto-snapshot
5. Some support plain TCP or encrypted TLS transport, I think that's unnecessary, SSH is enough
6. Some create ssh authentication wrapper script, I think that's unnecessary too, zfs allow is more secure
7. Some support unencrypted-to-encrypted or encrypted-to-unencrypted etc transformation between zfs send and zfs recv, I don't need that
8. Some need configuration file or configuration in ZFS properties
9. Tried some but I'm not smart enough to get them work

So I make another wheel, hope to keep it short and simple to understand.

Known limitations

1. DON'T zfs clone snapshots created by simple-zfs-repl, these snapshots are for floating mark. Create your own snapshots on source, they will be replicated to target.
2. DON'T directly create snapshots on target because they will be destroyed automatically by zfs recv -Fsv.

Other ZFS replication tools

Just for your reference, they have more features:

1. https://github.com/jimsalterjrs/sanoid/
2. https://github.com/bolthole/zrep
3. https://github.com/zrepl/zrepl
4. https://github.com/oetiker/znapzend/
5. https://github.com/jgoerzen/simplesnap
6. https://github.com/psy0rz/zfs_autobackup
7. https://github.com/alunduil/zfs-replicate
8. https://github.com/truenas/zettarepl
9. https://github.com/rlaager/zfs-replicate