[SOLVED] Resize ZFS for swap

[bolzerrr]

Hi,

i need some space for swapping, and following this guide it should be better outside the ZFS Raid1 (2 disks):
https://pve.proxmox.com/pve-docs/local-zfs-plain.html

What i was thinking of is to:
- remove one disk from the pool
- create 2 partitions on the removed disks (ZFS & swap)
- create a new pool on the first partition
- migrate drives from the old pool to the new pool
- tell Proxmox to boot from the new pool
- remove the old pool
- add the disk from the old pool to the new pool as raid member

This is just prototyping, i dont know if this a feasible at all, thats why i want to ask some more experienced memebrs here if this is feasible at all - or if there is even a better approach.

Thank you

 

[UdoB]

it should be better outside the ZFS Raid1

Yes.

There is no need to destroy and recreate a pool.

In this process you lose redundancy temporary. To avoid this you may simply work with a third disk if possible. In any case: make a Backup first ;-)

This is from my mind, not tested in this very moment. I'd done this a few week ago as I had to replace a mirrored vdev with smaller SSDs - which does not work inplace. Note that removing a top level vdev does work now, some years ago it was simply impossible. See man zpool-remove for details and for confirmation.

• remove one disk, the official way = not simply unplugging (not sure without testing: "zpool detach" or "zpool remove")
• prepare partition table as desired
• add the newly specified as a new vdev to the only pool. Note that this usually is not recommended - except in your specific case
• remove the old top level vdev - this will "free" the other disk
• partition that second disk
• attach it to the other partition to recreate the mirror

Note also that you did not have to move data by a specific command. It does happen as part of removing the old top level vdev, so be patient.

Good luck

 

[bolzerrr]

Thank you for your fint, but it doesnt work. The re-attached disk is for obvious reasons now smaller and cant be attached:
"cannot attach ata--part4 to nvme-part3: device is too small"
I guess i will now create a fresh pool on the resized disk and move everything around?! Or is there somne other way?
The actual data is way smaller then the disks size

 

[UdoB]

Okay. At the end it is: do it the way you are comfortable with.

My recipe said (in a crippled sentence) "add the newly specified as a new vdev" and what I meant was that you can always add a new vdev in whatever size - and this is usually not what you want to do. Your attempt to "attach" it to an already existing member is another thing. This would create a mirror and the attached device needs be at least the same size.

Your approach with a new pool is cleaner and easier, so... have fun!

 

[bolzerrr]

I followed this guide: https://aaronlauterer.com/blog/2021/proxmox-ve-migrate-to-smaller-root-disks/
And it was working perfectly, all done now!