RAID controller question...

[Joel Jaeggli]

Try insight systems www.insight.com, they have the dpt and the mylex
products...

joelja

On Tue, 8 Sep 1998, Stanley, Jeremy wrote:

> So far it appears that, for me, ICP Vortex is winning over DPT at a raw
> price level.  Admittedly this is not a very broad test since I'm only
> looking at internal PCI-SCSI controller cards (because my array is not
> hot pluggable, making the array-mount SCSI-SCSI impossible, and the
> rack-mount external boxes are a lot more expensive) and then only those
> that support low-voltage differential SCSI-3 drives (since that's what
> I've got).
> 
> The ICP Vortex I'm looking at is the GDT6518RD, which has been priced to
> me for $1245 by RAID Inc.
> 
> The DPT I'm considering is their PM3334UDW which they list for $1660,
> but I might find it cheaper if I can locate a reseller...
> 
> The Mylex controllers I looked at were of questionable compatibility for
> my array, and their answer-man is on vacation for a week, so they're
> conspicuously absent from my list for now.
> -------------------------*-------------------------
> Jeremy J. Stanley
> Information Systems Administrator
> Trend Community Mental Health Services
> 
> 
> > ----------
> > From: 	Christian Worley[SMTP:cworley@altatech.com]
> > Sent: 	Tuesday, September 08, 1998 3:11 PM
> > To: 	Michael Pearl
> > Cc: 	'Beowulf Cluster Mailing List'; 'Extreme Linux Mailing List'
> > Subject: 	Re: RAID controller question...
> > 
> > Michael Pearl wrote:
> > > 
> > > Have you looked at DPT's controllers?  I don't have performance
> > numbers,
> > > but I am currently running RAID-5 using a 2144UWR with RedHat 5.0.
> > > 
> > 
> > Michael,
> > 
> > Your system is in use, so performance testing may not be possible...
> > 
> > But, if you can destructively test your system, try (assuming your
> > raid is /dev/sda):
> > 
> > 	time dd if=/dev/zero of=/dev/sda count=65536 bs=65536
> > 
> > That will destroy any file system on /dev/sda, so don't do it on
> > anything but a new, destroyable, system (i.e., where you haven't run
> > "mke2fs" yet).
> > 
> > A similar test via a file system, assuming it's mounted on /dev/hd,
> > would be
> > 
> > 	time dd if=/dev/zero of=/mnt/hd/foo count=65536 bs=65536
> > 	rm /mnt/hd/foo
> > 
> > This would not be a destructive write test, but would include the
> > overhead of the file system and create a 4GB file.  Make sure to
> > delete the file: if you run this test twice without deleting the file
> > in-between, then you'll also measure the time for the file system to
> > delete such a file, which is not insignificant.
> > 
> > A read test, that won't destroy the system and won't be worst case
> > (because it won't show the overhead of calculating RAID-5 parity
> > stripes) would be:
> > 
> > 	time dd if=/dev/sda of=/dev/null count=65536 bs=65536
> > 
> > But that figure would be interesting too.
> > 
> > I test performance using the raw device since this uses only their
> > driver and not the file system overhead, even though that overhead is
> > negligible.  Given such a configuration, comparing RAID-0 to RAID-5
> > numbers shows the overhead brought on by the board and not the PCI bus
> > nor OS.
> > 
> > I've been told by the manufacturer that my test is not valid, since
> > it's not random (not reading and writing from random blocks) as normal
> > use would be.
> > 
> > I'd like to know of what real performance numbers (using the "dd"'s,
> > above) different RAID boards get.
> > 
> > Chris
> > -- 
> >   When I die, please cast my ashes upon Bill Gates
> >    --for once, let him clean up after me!
> > 
> 

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Joel Jaeggli				       joelja@darkwing.uoregon.edu    
Academic User Services			     consult@gladstone.uoregon.edu
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