Re: RAID 5+0 support

From: Martin Drab
Date: Thu Jan 19 2006 - 15:14:56 EST


On Thu, 19 Jan 2006, Phillip Susi wrote:

> Martin Drab wrote:
> > Speed is the issue here, I believe. By stripping two RAID-5 arrays you ought
> > to get the reliability of the RAID-5 but with considerably higher speed.
> > That's basically why RAID-50 exists, I think.
>
> One big raid-5 would have higher speed because it would have one more disk
> allocated to storing data rather than more parity. The raid 5+0 isn't really
> going to be any more reliable because it can withstand a single failure in
> either half, but not two failures in one half, so in the face of a double
> failure, you have a 50/50 chance of one being in each half.

Well, yes and no. See for instance:

http://en.wikipedia.org/wiki/RAID#RAID_50_.28RAID_5.2B0.29

Martin
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