Comment Re:RAID1 (Score 4, Interesting) 177
I've had disks fail almost all at the same time before.
It's really annoying when the following happens:
- Disk 1 dies in a RAID5 set
- Hot spare (Disk 4) comes online and starts rebuilding
- Disk 2 dies during the rebuild thrashing
- Rebuild never completes
- Put in 2 new disks
- Restore a backup
- Disk 3 fails during restoration, pulling in the hot swap (one of the new disks)
- A year later, the original hot spare (Disk 4) fails, leading to another rebuild
From my own experiences, the main culprit in these sorts of cases tend to be the bearings. Why they have a tendency to go at the same time, I have no idea. Haven't had it happen lately, but I know I'd rather avoid the problem.
Usually though, it's not the make/model/build date that is the issue, but the batch number (especially for the parts rather than the drive). Parts tend to get allocated in batches, so if you get a batch of say.... bearings, that aren't up to snuff, that batch of drives will probably fail earlier, while others (even ones manufactured on the same date) will be fine.
It's really annoying when the following happens:
- Disk 1 dies in a RAID5 set
- Hot spare (Disk 4) comes online and starts rebuilding
- Disk 2 dies during the rebuild thrashing
- Rebuild never completes
- Put in 2 new disks
- Restore a backup
- Disk 3 fails during restoration, pulling in the hot swap (one of the new disks)
- A year later, the original hot spare (Disk 4) fails, leading to another rebuild
From my own experiences, the main culprit in these sorts of cases tend to be the bearings. Why they have a tendency to go at the same time, I have no idea. Haven't had it happen lately, but I know I'd rather avoid the problem.
Usually though, it's not the make/model/build date that is the issue, but the batch number (especially for the parts rather than the drive). Parts tend to get allocated in batches, so if you get a batch of say.... bearings, that aren't up to snuff, that batch of drives will probably fail earlier, while others (even ones manufactured on the same date) will be fine.
