EVMS and degraded RAID

I’ve been very happy with EVMS under Linux; it’s an excellent way to coherently tie together lvm and md and other mirroring, striping, and logical volume technologies, and has a nifty GUI for managing drive resources. I move drives around much more than I like, often due to the grim reality of bad sectors or filesystem crashes.

After building a RAID volume, a loose power cable on one of the drives caused it to immediate degrade. This shouldn’t be a big deal, since EVMS has a “remfaulty” function for its RAID-5 plug-in. Except that it doesn’t work. I’m not sure whether it’s missing or broken in my version 2.5.5, but it doesn’t work as documented.

Looks like the way to fix this is through md directly, using mdadm. The tricky part about this is that one needs to refer to the EVMS controlled devices, or it doesn’t work. So, to re-add the drive and invoke the synchronization process, one needs to run:

mdadm --add /dev/md0 /dev/evms/.nodes/sda5

Note the “.nodes” part of the command