I am struggling with the concept on how the UI reports capacity as well
9 x 12 TB raidz2. Started with 4 disks, expanded the remaining disks one by one with no errors, no reboots.
“zpool list” shows 87 TB size, 29 TB free. UI shows “Usable Capacity:
42.5 TiB”, “Free Space: 13.63 TiB” - does not make any sense to me.
Does anybody know a workaround/fix to get the UI to be consistent with what the OS reports?
Unfortunately this is still an issue in 25.04
I just expanded a 4 wide raidz2 to 5 wide and was trying to figure out why almost an entire drives worth of available capacity was missing
I don’t know if this is an issue that will be fixed. You can read the other threads with the RAID-Zx-expansion tags to get an idea of what is involved with how the expansion happens and ZFS.
Maybe not fully fixed, but we are working on a nice change to zfs that will mitigate this and allow easier way to fix the reporting down the road, among other nice benefits
So in its current state it only removes the need to run a rebalance script on an expanded vdev, but doesn’t fix incorrect drive space reporting correct? But you’re saying it might make fixing the space reporting on an expanded vdev easier once that bug is taken on?
It may be healthier to acknowledge that there is no fix. While this can be fixed, I wouldn’t expect it within any reasonable interpretation of Soon™. You’re talking generational change. Maybe your descendants’ descendants will get to see it.
Longer explanation:
The borked space accounting was a deliberate decision by the main developer of raidz expansion (and one of the ZFS architects…) to make implementation easier.
To “fix” means reopening the case for raidz expansion… Expect similar time frames for delivery. At the VERY best. (For a realistic estimate, see @yorick above.)
I wouldn’t be quite as pessimistic… Based on what IX says, this could be fixed by changing the shrink value after running zfs rewrite - which has been merged and is slated for addition to 25.10.
