zpool upgrade - Not rpool


Apr 9, 2021
In a two node cluster configuration with node 1 installed with PVE 6 and recently upgraded to PVE 7.4. Both nodes are configured with ext4 as root filesystem and grup as bootloader. Both nodes also have a local zfs pool (non-root).

The node 1, even before upgrading to PVE 7.4 in response to zpool status command, suggested a zpool upgrade. I have been reading that a zpool upgrade can be unsafe with ZFS root filesystems, but for a non-root filesystem, is it safe/recommended perform this upgrade?
Could you please run zpool upgrade -v so to give an idea what are you missing?
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Regarding how safe it is, it is fine on pools which are not the boot device. Have in mind that once you upgrade the pool, it will no longer be accessible by older versions of zfs, so don't upgrade a pool if you plan on downgrading your system of moving it to a system using an older version of zfs. I would advice checking if there is a feature that benefits you before upgrading.
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Thanks @Maximiliano

I am not planning any downgrade on the system. The point is that node 1 replies to zpool status:

status: Some supported and requested features are not enabled on the pool.
The pool can still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
the pool may no longer be accessible by software that does not support
the features. See zpool-features(7) for details.

But node 2 does not.
When you created your filesystem on node 1 with ZFS you did so using (what would be now considered) an old version of ZFS so naturally it only has the features that were available at that moment. When you updated to Proxmox VE 7.4, ZFS was updated and it is able to detect that the file system is missing newer features.

Since node 2 was created with a more recent version of ZFS, from the point of view of node 2 it has the latest feature set and zfs status won't complain.
In fact, the zpool status showed that message at node 1even before the upgrading to PVE 7.

I guess that upgrading the non-root zpool at node 1 won't hurt it.


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