Small reminder: SW RAID-5 is crap on Linux
Yes, it is unusable. Slow when running in degraded mode and terribly
slow rebuild. It took approx. 2 days and 13 hours to rebuild 1TB
RAID-5 array with 4 *fast* disks. The system was next to unusable when
rebuilding.
This is the second time I realized that software RAID in Linux kernel
is unusable. I won't try it again despite what other people are
telling me.
And I was so naive that I wanted to wait for the completition of the
rebuild...
The next time this happens, I'll announce service outage to do a
complete restore from backups instead of rebuilding the array. It will
take me an hour or two...