Iain wrote:
As bytepile has it, failure of 1 disk in 0+1 leaves you with just RAID 0 so one more failure on the other pair and your data is gone. On the other hand, failure of 1 disk in raid 10 leaves you with a working raid 1 that can sustain a second failure.
What they're saying is in the case of (AsB) m (CsD) -- if A fails, they no longer count B as part of the array and no longer part of the possible drives that can fail. Sorta like the "no one hears a tree fall, did it fall" scenario.
I personally disagree with that theory. B is still part of the array. Pop in a new drive and the array is ready to start resync (CsD) --> (AsB). You still have a 1/3 chance in surviving another drive failure as long as B is the one that dies.
Although now that I think about it, RAID10 is more resillient because the odds are survival after 1 failure is 2/3. In the case of (AmB) s (CmD), if A fails, you can survive C failing or D failing.
---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend
