[CentOS] Question about a hard drive error

John R Pierce pierce at hogranch.com
Tue Nov 16 17:25:53 UTC 2010

On 11/16/10 8:31 AM, Benjamin Franz wrote:
> In these days of multi-terabyte drives you should be looking at RAID6
> instead. The chances of a 'double failure' during degraded
> operation/resync is too high to ignore.

These days of cheap drives, I use raid10 almost exclusively.  and if its 
at all mission critical, I like to have 1-2 hotspares.   if I was 
deploying a new server, and its workload was at all database-centric, 
I'd want to use use 2.5" SAS rather than 3.5" SATA

With RAID10, the rebuild time is how long it takes to copy the one 
drive.   if you have 6 drives in a raid10 and one fails, leaving 5, and 
another fails, there's only a 1 in 5 chance of that other failure being 
the mirror of the dead drive.       If you have a  hot spare, that 
rebuild starts immediately, reducing the window for that dreaded double 
failure to a minimum.

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