This is to be expected. RAID 5 is not safe. It is common for a RAID 5 array to be running in a degraded state during “normal” operation without the operator’s knowledge. Then, when one drive fails, rebuilding the array is impossible; you have already lost data.
This is common because there is often no good way to repair a RAID 5 system which is running in degraded state, and there is often no monitoring to respond to array degradation (if you can’t fix it, why monitor it?)
In other words, RAID 5 does not protect very well against drive failures. RAID 6 is more durable but inefficient (there are systems which are both more durable and more efficient than RAID 6). RAID is generally optimized for implementation simplicity over other concerns.
I'm having trouble with some of what you're saying. Why is RAID 5 any different than, say, RAID 1? You monitor them both the same way (your raid controller tells you it's degraded), and you fix both the same way (slam in a new drive and rebuild). Why would monitoring/recovery be any different than any other RAID level on a controller?
klodolph|5 years ago
This is common because there is often no good way to repair a RAID 5 system which is running in degraded state, and there is often no monitoring to respond to array degradation (if you can’t fix it, why monitor it?)
In other words, RAID 5 does not protect very well against drive failures. RAID 6 is more durable but inefficient (there are systems which are both more durable and more efficient than RAID 6). RAID is generally optimized for implementation simplicity over other concerns.
parliament32|5 years ago
tutfbhuf|5 years ago
RAID 10?
sliken|5 years ago