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Run regular raid consistency checks. I run this on tuesday night. Edit your crontab. Run regular raid consistency checks. This will detect the bad sectors before they become a problem. I run this on tuesday night. Edit your crontab.

KVM Host Raid Consistency Checking

The Problem

Eventually a disk will fail, but in some cases a sector on a disk just goes bad without being used, and noone knows...

Consider the following.

  • A sector on disk A goes bad. The sector is not used yet.
  • A sector on disk B goed bad. The sector on disk B is used.
  • Raid software will take disk B out of the array.
  • A new disk is added to replace disk B.
  • Resyncing from disk A to disk B is started.
  • Resyncing reaches bad sector on disk A,
  • Resyncing is now impossible.

The solution

Run regular raid consistency checks. This will detect the bad sectors before they become a problem. I run this on tuesday night. Edit your crontab. 

# crontab -e

Add the following to your crontab 

0 4 * * 2 echo "check" > /sys/block/md0/md/sync_action
0 4 * * 2 echo "check" > /sys/block/md1/md/sync_action

None: KVM Host Raid Consistency Checking (last edited 2017-11-11 20:08:10 by shran)