Replacing 3 disk ZFS pool in one go

[mha]

Hi,

I am running TrueNAS-12.0-U8 booting from a USB stick and have a ZFS pool with 3 disks running (think it is called RaidZ) - 1 disk fault tolerance).

I had a batch of old 2TB disks which I wanted to use up and kept replacing/resilvering single failing disks every few month. Now I ran out of old disks and decided to buy 3 new WD Red One Plus 2TB disks. I have a full backup of the pool on a separate 4TB HDD.

What is the best strategy to replace the still running 3 old disks with the new ones? Replacing/resilvering one by one? Or is there a better way to do this?

Thanks,
Michael

 

[Etorix]

If you have free SATA ports you may plug in the new drives without removing the old ones and select 'Replace' (Storage>Pools>(gear)>Status>(drive)>(…)>Replace). All three drives in one go if you have three spare ports.
Mind that raidz1 becomes less safe with larger drives and consider moving to raidz2 at some point.

 

[mha]

Thanks for your reply. Unfortunately I only have 4 SATA ports. So back to replacing/resilvering one by one?

For RaidZ2 I'd need 4 disks, right?

 

[Etorix]

Correct on both counts.
There's no way to change a raidz1 into a raidz2, so if you go this way you'll have either to (a) backup, delete the raidz1 pool and restore to the new raidz2, or (b) to get a HBA (or another server…) to attach all drives (at least temporarily) and transfer (replication) from one pool to the other.

 

[mha]

Thanks.

Backup: I have one spare SATA port and a spare old 4TB disk. Is this a reasonable way to backup the RaidZ1 and restore to a new RaidZ2:
- connect 4TB disk to USB
- create ZFS pool and dataset on 4TB drive
- snapshot the existing RaidZ1 pool
- replicate snapshot to 4TB dataset
- tgurn off, exchange disks (now 4 new ones), turn on
- create ZFS pool RaidZ2 on new disks
- create snapshot on 4TB disk
- replicate to raidZ2 pool

will the shares and things work again?

 

[Etorix]

Datasets will be preserved. You may need to point shares to the new pool.

 

[mha]

Thanks for your help!