RAID controller question...

[Joel Jaeggli]

Mylex  has a new lvd controller. Not sure about support for linux, but at
the moment I kind of doubt it since it seems to be based around a
strongarm risc core rather than one of their standard chipsets...

joelja

On Wed, 9 Sep 1998, Stanley, Jeremy wrote:

> 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
> >      PGP Key Fingerprint: 1DE9 8FCA 51FB 4195 B42A 9C32 A30D 121E
> > ----------------------------------------------------------------------
> > ----
> > It is clear that the arm of criticism cannot replace the criticism of
> > arms.  Karl Marx -- Introduction to the critique of Hegel's Philosophy
> > of
> > the right, 1843.
> > 
> > 
> 

-------------------------------------------------------------------------- 
Joel Jaeggli				       joelja@darkwing.uoregon.edu    
Academic User Services			     consult@gladstone.uoregon.edu
     PGP Key Fingerprint: 1DE9 8FCA 51FB 4195 B42A 9C32 A30D 121E
--------------------------------------------------------------------------
It is clear that the arm of criticism cannot replace the criticism of
arms.  Karl Marx -- Introduction to the critique of Hegel's Philosophy of
the right, 1843.