ZFS...

Miroslav Lachman
Thu, 09 May 2019 08:32:19 -0000

Patrick M. Hausen wrote on 2019/05/09 09:46:
> Hi all,
>
>> Am 09.05.2019 um 00:55 schrieb Michelle Sullivan <michelle at
sorbs.net>:
>> No, one disk in the 16 disk zRAID2 ...  previously unseen but it could
be the errors have occurred in the last 6 weeks... everytime I reboot it started
resilvering, gets to 761M resilvered and then stops.
>
> 16 disks in *one* RAIDZ2 vdev? That might be the cause of your insanely
> long scrubs. In general it is not recommended though I cannot find the
> source for that information quickly just now.

Extremely slow scrub is an issue even on 4 disks RAIDZ. I already posted
about it in the past. This scrub is running from Sunday 3AM.
Time to go is big lie. Is was "19hXXm" 12 hour ago.

   pool: tank0
  state: ONLINE
   scan: scrub in progress since Sun May  5 03:01:48 2019
         10.8T scanned out of 12.7T at 30.4M/s, 18h39m to go
         0 repaired, 84.72% done
config:

         NAME                STATE     READ WRITE CKSUM
         tank0               ONLINE       0     0     0
           raidz1-0          ONLINE       0     0     0
             gpt/disk0tank0  ONLINE       0     0     0
             gpt/disk1tank0  ONLINE       0     0     0
             gpt/disk2tank0  ONLINE       0     0     0
             gpt/disk3tank0  ONLINE       0     0     0

Disks are OK, monitored by smartmontools. There is nothing odd, just the
long long scrubs. This machine was started with 4x 1TB (now 4x 4TB) and
scrub was slow with 1TB disks too. This machine - HP ML110 G8) was my
first machine with ZFS. If I remember it well it was FreeBSD 7.0, now
running 11.2. Scrub was / is always about one week. (I tried some sysctl
tuning without much gain)

Miroslav Lachman