RAID And You (A Guide To RAID-0/1/5/6/xx)

[stevecs]

Actually, found a couple web documents here that may prove to be interesting to others creating arrays:

Draft write up of "silent" data errors (not only for disk but the entire chain of the process):
http://indico.cern.ch/getFile.py/acc...r&confId=13797

Failure rates on drives:
http://www.usenix.org/events/fast07/...tml/index.html

Another failure rate study:
http://209.85.163.132/papers/disk_failures.pdf

Pretty much shows that:
1) if you need to have data accurate you need to _ALWAYS_ verify it before, during, after, use as no subsystem will give you correct data 100% of the time.

2) MTTF, AFR, are not good paper specs to "buy" off of.

3) Older drives than rated lifetime or drives that have reported an error/reallocation should be replaced/removed due to the dramatically higher failure rates.