zpool status with cksum errors on two drives in a mirror

[rreboto]

Hello,

I have a pool with a mirrored pair. After running zfs scrub I see that both drives in the pool have checksum errors, but the mirror itself does not show checksum errors:

Code:

config:

    NAME        STATE     READ WRITE CKSUM
    tank        ONLINE       0     0     0
      mirror-0  ONLINE       0     0     0
        sda     ONLINE       0     0   425
        sdb     ONLINE       0     0   443

errors: No known data errors

Am I to interpret this as, the data in the pool is safe because some blocks that are bad on sda are okay on sdb and some bad blocks on sdb are okay on sda?

This also means I should replace both drives, correct?

Thank you!

 

[Ericloewe]

Yeah, pretty much. The errors are in different places and ZFS presumably recovered everything. The header for zpool status probably said how much was repaired, exactly.

And yeah, replacements would be good.

 

[sretalla]

Checksum errors can indicate connectivity issues more clearly than data issues.

Make sure you run smartctl -a on your drives to ensure there are actually errors on them.

It may be cabling or the controller that's bad.

 

[Ericloewe]

I'm not sure about that. A read or write error would be reported if the interface detects a transmission error it can't recover from.

 

[rreboto]

The header for zpool status probably said how much was repaired, exactly.

Yep; it's not a lot of data in this pool, but still kinda nice to see ZFS's magic at work:

Code:

  scan: scrub repaired 2.79M in 00:03:30 with 0 errors on Wed Dec 16 01:17:52 2020

And yeah, replacements would be good.

Thanks for confirming; will order new drives.