On Sun, 2009-10-25 at 14:52 -0400, Ron Loftin wrote: > On Sun, 2009-10-25 at 12:33 -0600, Devin Reade wrote: > > Saturday I did an upgrade from 5.3 (original install) to 5.4. Saturday > > night, /etc/cron.weekly reported the following: > > > > /etc/cron.weekly/99-raid-check: > > > > WARNING: mismatch_cnt is not 0 on /dev/md0 > > > I had this happen on a box that I upgraded Friday. I went ahead and > tested each partition in the affected mirror with badblocks ( found no > errors ) and after multiple resyncs, there was no change. After similar > experiences with Google, I did run across a note saying that this went > away after a reboot. I broke down and applied the Micro$lop solution > ( reboot ) and the error has gone away. > > Like you, I'm interested in a better understanding of this issue, so if > anyone else has more info, I'm all ears. ;> > mismatch_cnt (/sys/block/md*/md/mismatch_cnt) is the number of unsynchronized blocks in the raid. The repair is to rebuild the raid: # echo repair >/sys/block/md<#>/md/sync_action ...which does not reset the count, but if you force a check after the rebuild is complete: # echo check >/sys/block/md<#>/md/sync_action ...then the count should return to zero. Or at least that worked for me on three systems today. Steve