[zfs-discuss] cannot import 'home': I/O error Destroy and re-create the pool from a backup source

Bryn Hughes zfs at nashira.ca
Fri Apr 27 15:13:45 EDT 2018

On 2018-04-27 11:20 AM, Anton Gubar'kov via zfs-discuss wrote:
> I still fail to understand the meaning of CKSUM errors on radiz0 vdev 
> and pool levels. Can someone explain this to me? Before I understand 
> these numbers I discard them as non credible (noise).

CKSUM errors mean the data read from the device did not match the 
checksum that ZFS wrote when it wrote the data, meaning the data is 
corrupted. The read operation completed successfully without error (as 
in it said "read me these disk blocks, and the disk responded with data 
rather than an error), however the data that was read back is faulty. 
Normally you should not see any checksum errors at all; the only time I 
see any on my system for instance is when a disk fails causing the bus 
to reset.

When ZFS encounters a checksum error it will attempt to read the data 
from another device (in the case of a mirror), or reconstruct the data 
from parity (in the case of RAIDZn). If your system was operating 
previously and those CKSUM error numbers were increasing you were 
actually seeing ZFS doing its job despite adverse conditions. Were you 
seeing CKSUM errors before this problem started?

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