[cvsnt] performence problem

[John Peacock]

Peter Crowther wrote:

> - RAID '10' (duplexed RAID 5) for repository - or, if performance is your *absolute* requirement, duplexed RAID 0 and watch like a hawk for disk failures!
> For extra points, make the mirrors duplexed, i.e. on different controllers.

Just to pick nits here, RAID 10 (often referred to as 1+0) has nothing 
whatsoever to do with RAID 5.  RAID 5 includes distributed parity on 
each drive and a single drive failure is easy to recover from.  RAID 1+0 
is a mirrored (for maximum reliability) set of striped drives (for 
maximum performance), where multiple drive failures are recoverable 
(under certain circumstances).  Here's a good link with nice graphics:

	http://www.acnc.com/04_01_10.html

RAID 1+0 works very well with dual controllers so that the mirrored 
writes can be absolutely parallel.  Don't confuse RAID 1+0 with 0+1 
which is _not_ the same thing; I think your reference to "duplexed RAID 
0" is what most people refer to as 0+1.

Just FYI

John