Mdadm is my favorite friend but there is something that annoys me terribly – periodic inspections and resink health of the RAID array- for example there is data in bad sectors, which in turn crushes the machine from to IO. In general, after picking, I found the culprits – crowns that usually start around 1pm every Sunday. The idea is clear – assurance that the array is in perfect condition and there is no drama with the information. This is good, but I see a lot every week, so I reconfigured it to run every first date of the month.

For Redhat based derivatives the path to the crown is /etc/cron.d/raid-check. For Debian based distros, the path is /etc/cron.d/mdadm. Crowns, in turn, call bash scripts /usr/sbin/raid-check for CentOS etc and /usr/share/mdadm/checkarray for Debian and friends. Parameters to the scripts are taken from /etc/sysconfig/raid-check or respectively /etc/default/mdadm where the check can be completely banned, which is not very clever as an idea.

 

2 fast RAID 5 advice

  1. If you have RAID 5 system keep the disks in MBR instead of in GPT – at least he gave it to me +10 – +15% difference
  2. Be sure to set / sys / block / md0 / md / stripe_cache_size because it is too small by default. Here the values ​​are according to depends on me 32768 gave the most decent result