[CentOS] RAID 5 setup?

John R Pierce pierce at hogranch.com
Fri Mar 26 02:12:00 UTC 2010

Christopher Chan wrote:
>> but with RAID 10, data is safe after many types of failures.
> Except for the case when a mirror dies after which the whole thing is 
> toast but in theory you can survive up to four disks going down.

if you have a 8 drive raid1+0, and a random drive fails, you can survive 
any other drive failing *except* the mirror of the failed one.   so if a 
second drive fails, there's only a 1 in 7 chance that its the 'fatal' 
one.   on a 4 drive raid10, its a 1 in 3 chance.   meanwhile, a raid10 
can rebuild from a hotspare in like an hour, if the system isn't busy, 
and a few hours in the background if its busy and active.

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