Upgrade ZFS from 0.8 to 2.3.0 version

OpenZFS
1

I’m going to upgrade an old server from ZFS 0.8 to version 2.3.0 and want to clarify a few key points before proceeding.

If anyone has experience upgrading from 0.8 to 2.3.0, I’d greatly appreciate your insights.

  1. Are there any particular steps in the upgrade process, both before and after, besides running zpool upgrade?
  2. Is it necessary to stop any load (read/write operations) on the filesystem during the upgrade?
  3. Have there been any failures when upgrading ZFS to version 2.3.0 (data loss or corruption)?
2

I would expect that your zfs pool would import fine. The pool status would show that the new feature flags could be applied with pool upgrade. Once you do this, new records or filesystems created in the pool will begin to gain these properties.

If you do a zfs send to your backup machine and are sending newer properties than the backup pool supports, you might have to adjust what your zfs send command is doing.

You could test this by crafting a small temporary pool on removable media and test your backup procedure on it.