[CentOS] RAID 6 - opinions

Thu Apr 11 16:03:44 UTC 2013
John Doe <jdmls at yahoo.com>

From: Joseph Spenner <joseph85750 at yahoo.com>

> A RAID5 with a hot spare isn't really the same as a RAID6.  For those not 
> familiar with this, a RAID5 in degraded mode (after it lost a disk) will suffer 
> a performance hit, as well as while it rebuilds from a hot spare.  A RAID6 after 
> losing a disk will not suffer.  So, depending on your need for performance, 
> you'll need to decide.
> As far as having a spare disk on a RAID6, I'd say it's not necessary.  
> As long as you have some mechanism in place to inform you if/when a disk fails, 
> you'll not suffer any performance hit.

Also, if you lose a disk, the RAID6 can lose a second disk anytime without problem.
The RAID5 cannot until the hot spare has fully replaced the dead disk (which can take a while).
And, I believe RAID6 algorithm might be (a little) more demanding/slow than RAID5.
Check also RAID50 and 60 if your controller permits it...