What the heck is <0xffffffffffffffff>:<0xa0>

[ERM-Consulting]

One of our systems have had a controller down.
We changed the controller and repaired the zfs with scrub.
Everything seemed to be ok, but with

zpool status -v
we get following message:

pool: zDataStorage8
state: ONLINE
status: One or more devices has experienced an error resulting in data
corruption. Applications may be affected.
action: Restore the file in question if possible. Otherwise restore the
entire pool from backup.
see: http://illumos.org/msg/ZFS-8000-8A
scan: scrub repaired 0 in 1 days 13:34:32 with 0 errors on Fri Sep 24 07:25:04 2021
config:

NAME STATE READ WRITE CKSUM
zDataStorage8 ONLINE 0 0 64.4K
raidz1-0 ONLINE 0 0 0
da1 ONLINE 0 0 0
da2 ONLINE 0 0 0
da3 ONLINE 0 0 0
raidz1-1 ONLINE 0 0 129K
da4 ONLINE 0 0 0
da5 ONLINE 0 0 0
da6 ONLINE 0 0 0
raidz1-2 ONLINE 0 0 129K
da7 ONLINE 0 0 0
da8 ONLINE 0 0 0
da9 ONLINE 0 0 0

errors: Permanent errors have been detected in the following files:

<0xffffffffffffffff>:<0xa0>

We do not know, if we have to restore our pool due to this message.
=> we transfer all snapshots to a backup-pool. That pool is totally ok so the error is not transported to the backup.

 

[sretalla]

We do not know, if we have to restore our pool due to this message.

Well, that corruption is in metadata.

Based on an all-Fs address, my guess is that it's the backup space map (which I think is stored at the end of the address space, as opposed to the "real one" stored at the beginning... all-0s address).

If it were my pool and I already had a backup which I had confidence in (like it seems the case is for you), I would rebuild the pool and restore the contents.

I don't expect that's an emergency, but I wouldn't just leave it like that.