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From: Peter Boettcher <boettcher@ll.mit.edu>
Newsgroups: comp.soft-sys.matlab
Subject: Re: MATLAB and RAID
References: <gr20s5$gn5$1@fred.mathworks.com>
Message-ID: <muy7i238aca.fsf@G99-Boettcher.llan.ll.mit.edu>
Organization: MIT Lincoln Laboratory
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Date: Thu, 02 Apr 2009 09:16:21 -0400
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"Andre Weideman" <weideman@dip.sun.ac.za> writes:

> I got a new Dell Precision T3400 Quad Core 2, with RAID technology
> (two disks, 320 Gig each).    I can set it up as RAID-0, RAID-1, or just
> use the second disk as a storage facility.  I would like to optimize speed
> in MATLAB (primarily floating point computations).     What should I do?
> Wikipedia tells me that RAID involves computations that could reduce my 
> processing speed.  Would this offset the additional speed  offered by
> RAID-0?   I am pretty much an ignoramus here.   Thanks for any advice.

Completely irrelevant.  If you are optimizing floating point
computation, (and have enough memory) then you are not even accessing
the disk.

Even when you do, the hardware disk controller handles the RAID
computations for you, so the CPU doesn't have to.  And even then,
neither RAID-0 nor RAID-1 involve any computations.  RAID-0 alternates
(stripes) data across the drives, while RAID-1 simply puts the same
stuff on both.

Using RAID-0 will speed up reads of large data.  It may not make much
difference for opening lots of small files, like when you boot your
computer or start MATLAB.  Only use this for your boot drive if you have
a solid nightly backup system.

RAID-1 is what I would use for a boot volume, where you store all your
documents, programs, etc.  If one drive dies (sometime in your life, you
will very likely have a failed drive) just replace the one, let the
controller re-duplicate, and get back to work.  RAID-1 *does* help with
read speed (similar to RAID-0), but slows down write speed.

-Peter