[AccessD] WHS on Raid

Michael,

XP and above will do a software raid.  The problem with all such raids is
that the read and in particular the WRITE times are abysmal as in under 5
mbytes / sec, whereas any single disk usually has a read / write time in the
neighborhood of 40-60 mbytes / second.  I think what is going on is that the
raid process requires a lot of computation (called an XOR compute) that has
to be done by the processor if there is no hardware assistance (dedicated
co-processor).  I am guessing that MS throttles that process to avoid using
all of the processor time in doing this processing.  That was probably
necessary back in 2002 when XP hit the scenes but now we have 4X the power
and 2-4X the cores and it is my opinion that the software raid or software
assisted raid (controllers without the co-processor) could probably work
very well and very fast IF MS would let the XOR processor have more
processor time.

Just speculation of course.  What I know for sure is that I ran software
raid and it was so bad that it was essentially unusable (Raid 5).  I think
people do use Raid 0 but that has no data protection, it is all about
speeding up reads.  I need Raid 5 or 6 and doing that without a hardware
co-processor is just not possible at this time.


John W. Colby
Colby Consulting
www.ColbyConsulting.com 
-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Michael Bahr
Sent: Sunday, December 30, 2007 5:52 PM
To: Access Developers discussion and problem solving
Subject: Re: [AccessD] WHS on Raid

Hi John, I found this link that uses XP Pro for software raid.  Apparently
this feature has been disabled in XP.

http://www.tomshardware.com/2004/11/19/using_windowsxp_to_make_raid_5_happen
/

Mike...