“Measurements at CERN (using Linux)
● Wrote a simple application to write/verify 1GB file
● Write 1MB, sleep 1 second, etc. until 1GB has been written
● Read 1MB, verify, sleep 1 second, etc.
● Ran on 3000 rack servers with HW RAID card
● After 3 weeks, found 152 instances of silent data corruption
● Previously thought “everything was fine”
● HW RAID only detected “noisy” data errors
● Need end-to-end verification to catch silent data corruption”

http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt
“When a drive returns garbage, since RAID5 does not EVER check parity on read (RAID3 & RAID4 do BTW and both perform better for databases than RAID5 to boot) if you write a garbage sector back garbage parity will
be calculated and your RAID5 integrity is lost! Similarly if a drive fails and one of the remaining drives is flaky the replacement will be rebuilt with garbage also propagating the problem to two blocks instead of just one.”

http://74.125.77.132/search?q=cacheA0-6Ufp8a8J:gridmon.dl.ac.uk/nfnn/slides/RichardHughesJonesNFNN2.pdf+%22One+failure+for+every+10**15+bits+read%22&hl=sv&ct=clnk&cd=2&gl=se

“One failure for every 10**15 bits read. 1 week). Data loss possible”