RAID controller question...

[Stanley, Jeremy]

Thanks for the lead...  Insight had the DPT PM3334UDW for $1275 which
puts it in the same price range as the ICP GDT6518RD.  As for Mylex,
their MY906256 looks nice, but I can't find anywhere if it's compatible
with LVDS.  For that matter, none of Mylex's RAID controllers I looked
at (those under $2000) claim anything about LVDS.  If anyone knows
whether or not Mylex supports it, I'd appreciate the info.  Thanks in
advance.
-------------------------*-------------------------
Jeremy J. Stanley
Information Systems Administrator
Trend Community Mental Health Services


> ----------
> From: 	Joel Jaeggli[SMTP:joelja@darkwing.uoregon.edu]
> Sent: 	Tuesday, September 08, 1998 6:02 PM
> To: 	Stanley, Jeremy
> Cc: 	Michael Pearl; 'Christian Worley'; 'Beowulf Cluster Mailing
> List'; 'Extreme Linux Mailing List'
> Subject: 	RE: RAID controller question...
> 
> 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!
> > > 
> > 
> 
> ----------------------------------------------------------------------
> ---- 
> Joel Jaeggli
> joelja@darkwing.uoregon.edu    
> Academic User Services
> consult@gladstone.uoregon.edu
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