The latest release of UrBackup (2.2.7) has a new feature which we requested and sponsored: ZFS-based filebackups. UrBackup supported image-backups to ZFS volumes before, but we feel that ZFS snapshots make UrBackup better suitable for large environments because it depends on hardlinks less.
When you enable ZFS backups, each backup UrBackup makes has its own filesystem. A following backup will be created with the last backup as ‘ZFS origin’, so all files that were unchanged are already in place. New files will be added, changed files overwritten and removed files deleted. Removing an old backup is as simple as removing the snapshot.
Migrating to the new method
Even migration is taken care of. First, setup ZFS images and ZFS filebackups as described in the admin manual. You will notice that a new backup of each client will take much longer. This is because UrBackup will create a new filesystem and copy the latest backup it made as the origin. So make sure you have enought space to do this! Your backup space will probably take up about two/third of the current usage extra.
This method has a drawback, albeit a small one. The default setup of UrBackup creates hardlinks between various clients if files are identical. So if you have a file on every client, UrBackup will only store it once. But we feel storage is cheaper than the performancehits all this hardlinking causes.
We thank Martin Raiber for creating this great software, and we’re very happy to be able to sponsor his project. We hope everyone remembers to sponsor open source software every now and then.