Re: detecting read errors after RAID1 check operation

On Wednesday August 15, maccetta@laurelnetworks.com wrote:

There are already files like /sys/block/md_d0/md/dev-sdb/errors in /sys
which would be very convenient to consult but according to the kernel
driver implementation the error counts reported there are apparently
for corrected errors and not relevant for read errors during a "check"
operation.

When 'check' hits a read error, an attempt is made to 'correct' it by
over-writing with correct data.  This will either increase the
'errors' count or fail the drive completely.

What 'check' doesn't do (and 'repair' does) it react when it find that
successful reads of all drives (in a raid1) do not match.

So just use the 'errors' number - it is exactly what you want.

NeilBrown