Before setting up my 1st unraid, I watched a lot of YouTube videos, mostly SpaceInvader One. I came to unraid around 6.10 or 11. At the time there was a lot of buzz about zfs.

I set up all my array drives as zfs, which I now realise may not have been the best idea.

My array drives are split across 2 sabrent usb drive cages, again I know not a best case scenario! I had the hardware before I ever knew about Unraid- that's my excuse....

One of the cages has caused issues a couple of times, with drive 8 going offline a few times. I have that drive replaced with a similar drive in a different slot- the old drive 8 precleared no problem, so not sure if it was the drive or the slot.

So my array has 13 8TB drives, 2 for parity. Some drives have a significant list of zfs errors, which obviously cannot be "repaired" as there is no redundancy for zfs as they are array drives and not a pool.

I did run a scrub on one drive, but the errors are still there. To be clear everything is working well as far as I can tell. My unraid is mainly used for movie and TV "cord cutting".

I have been considering swapping to xfs for my array drives, which is seems I should have started with?

I was thinking stop the array, start it with one drive missing, reformat that drive as xfs and then add it back to the array. I understand that will take considerable time to rebuild all 11 drives and would be a very bad idea with only one parity drive.

My question I guess is, should I bother? I know zfs wasn't the best choice, but was it a bad enough choice to put the array through 11 data rebuilds??

Thanks for your thoughts.

You cannot change the file system used by an array drive using a rebuild - the rebuild always rebuilds the original file system. You first have to empty a drive of any data you want to keep after which you can then reformat the drive to a different file system (which only take a few minutes). You may then need to copy the data back. Parity stays valid throughout so only having a single parity drive is not an issue. This is akin to the process used to migrate from reiserfs to xfs in the array, but it is very time consuming.

Whether you want to do this is up to you. As you said having zfs is not recommended in the array as zfs format in the main array does not perform well and the normal zfs recovery mechanisms available to redundant zfs pools are not available due to each arrays drive being a free-standing file system. Normally you only want zfs in the main array (if at all) to make a drive capable of receiving zfs snapshots.

2 hours ago, IanMcLeish said:

Some drives have a significant list of zfs errors

This would suggest a hardware problem, most often bad RAM, so I would recommend investigating this first.

If you ahve enough space you can use the mover to empty an array drive, format it, then move on to the next one