From owner-freebsd-fs@FreeBSD.ORG  Fri Jun 10 08:55:43 2011
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Date: Fri, 10 Jun 2011 09:43:14 +0100
From: Karl Pielorz <kpielorz_lst@tdx.co.uk>
To: freebsd-fs@freebsd.org
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Subject: ZFS scrub 'repaired' pool with no chksum or read errors?
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Hi,

I'm running FreeBSD-8.2R amd64 w/4Gb of ECC RAM on a machine used for 
'offsite' backups (that are copied to it using zfs send/receive).

I scrub this machine every now and again (about once a month) - recently 
this resulted in the following output after the scrub completed:

"
# zpool status
  pool: vol
 state: ONLINE
 scrub: scrub completed after 2h49m with 0 errors on Thu Jun  9 17:09:31 
2011
config:

        NAME        STATE     READ WRITE CKSUM
        vol         ONLINE       0     0     0
          raidz1    ONLINE       0     0     0
            ada0    ONLINE       0     0     0  256K repaired
            ada1    ONLINE       0     0     0
            ada2    ONLINE       0     0     0

errors: No known data errors
"


Should I be worried there was 256k of 'repairs' done, even though there 
were no checksum errors, or read errors detected?

The console logged no errors - and nothing shows in syslog.

The machine is always cleanly shut down - and the drives all appear fine 
from a SMART point of view - I'm just a bit concerned as to where the 
repairs came from - as ZFS doesn't seem to know (or be able to tell me) 
either :)


-Kp