[PVE-User] zfs raidz2 expansion

[Aaron Lauterer]

You can always add a new  VDEV to the pool (man zpool-add). Expanding a 
raidz2 VDEV itself is only possible with ZFS 2.3 AFAIU and we do not 
ship that yet [0].

But if this is for VM storage, you might want to consider a ZFS pool of 
multiple mirrored VDEVs. [1] has more details.

While performance might not be much of an issue anymore with recent 
NVMEs that provide a ton of IOPS, the additional space usage might still 
be something to think about in a raidz pool used for VMs (ZVOL).


[0] 
https://forum.proxmox.com/threads/proxmox-ve-8-4-released.164821/#post-762367
[1] 
https://pve.proxmox.com/pve-docs/pve-admin-guide.html#sysadmin_zfs_raid_considerations

On  2025-05-20  03:24, Randy Bush wrote:
> running 8.4.1 with images on 4x2tb raidz2 ssds (zfs-2.2.7-pve2).  we
> want to double the space.  the net of a million lies says all sorts of
> things about expanding raidz2.  as we do full replication, we could just
> create a new pool for replocation and call it a day.  but i am curious
> if we can just expand the current pool.  my reading says doubtful, but
> am not deeply clued.
> 
> randy
> 
> ---
> 
> https://forum.proxmox.com/threads/raidz-expansion.135413/
> https://github.com/openzfs/zfs/pull/15022
> 
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