I am going to set up a new zpool. I plan to use nested datasets to store individual files. For example I could have the following datasets:


tank is the zpool itself, it contains no files, instead, all files are stored in the datasets like tank/homes/user and so on. Now I want to set up a proper backup for this. The problem is that the zpool will be large (100T) and therefore, the incremental backup will take a long time, therefore the files can change during the backup and the backup agent will then retry the backup, which slows it further down etc. So I planned to make a snapshot, like zfs snap tank@backup, then use the snapshot to perform the backup, and then destroy the snapshot afterwards. However, this does not work, as the snapshot tank@backup will not contain the sub-datasets like tank/shares or tank/shares/pub. However, with zfs snap -r tank@backup I get recursive snapshots, but I cannot use these, as it will be messy for the restore of the backup.

Unfortunately, I cannot use zfs send and zfs receive for the backup, as I use IBM Tivoli / Spectrum Protect for the backup, i.e. dsmc, which, to my knowledge, needs files to backup, and I believe it won't work with zfs send.

So I believe, I will probably end up with just backing up /tank/*, e.g. something like dsmc incremental /tank/* -subdir=yes, which ignores all ZFS features and will backup datasets like ordinary folders and so on.

Is there probably a better method?

  • One might be able to backup each dataset on its own, with their own snapshots; to avoid changing files. NetApps can backup ndmp-dumps in TSM^wSpectrum Protect. That avoids seeking for changed files. Maybe one can generate ndmp-dumps (with the help of zfs-snapshots) to send them into Spectrum Scale.
    – rathier
    Oct 1 at 17:10
  • I forgot: ndmp backup does not backup single files but dumps of a filesystem; so it is more suited for desaster recovery. one would need organize file based backup/restore via snapshots.
    – rathier
    Oct 1 at 17:24


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