Morning all, I have a Truenas CE 25.10.3 - with 1 x Pool and 3 x VDEVs:
It has had a failed disk for a while (being non-production). However this morning I believe it has dropped another disk.
All show in DRAC as fine, however it now shows the pool as EXPORTED, and it is showing as another drive dropped from the pool (so now unassigned).
Can anyone advise how to get the missing drive back into the EXPORTED pool, then recreate the VDEV from this. Need to get back to this:
Any help appreciated.
First off, you never want to “add” an existing data disk back into a vDev. ZFS either finds it automatically, or the disk has lost too much data for ZFS to use it.
Next, using RAID-Z1 means you can loose only 1 disk in each vDev, before DATA LOSS. It appears you have lost 2 disks in the same RAID-Z1 vDev, otherwise the pool would still be available.
Please supply the output of zpool import command, in CODE tags. With that, we can see more clearly the pool state.
Thanks Arwen, I think we have lost the data unfortunately.
Hopefully there is a way. If not, I will be re-building as RAIDZ2 like my other NAS, so there will be more tolerance going forward.
Try sudo zpool import. You’re attempting this as non-root.
Thanks Samuel. I am sure you are going to tell me to start again. If so I am going to use 14 x disks, RAIDZ2, 2 VDEVs, 6 wide.
You may want to rebuild your pool as 3-wide VDEVs of 4-wide RAIDZ2s, with 2 spares. This will give you both more capacity and more throughput, and able to survive up to 4 failed disks in any VDEV.
Hi Samuel, in the table I saw, 4 wide VDEVs only give 50% usable space.
But 6 wide VDEVs give 67%.
Is that not right?
You have to look at the total capacity afterwards:
3x VDEVs of 4-wide RAIDZ2 14 TB disks: 3 x 50%(4 x 14 TB) = 3 x 28 TB = 84 TB
Plus you’ll get 50% better throughput.
Makes sense! Thanks for your help Samuel.
