[svlug] Following up backup, let's talk RAID controllers ...

Bryan -TheBS- Smith thebs at theseus.com
Tue May 23 12:49:48 PDT 2000

Following up backup, let's talk RAID controllers ...

My current system has a 2-channel (plus 1, non-RAID channel) Ultra2
SCSI controller from ICP-Vortex.  All-in-all, this controller has
done a fine job, and any problems with performance has been a
result of two things:
   1.  NFS v2 to the Solaris clients (my main data pushers)
   2.  Use of a $100 mainboard in a $10K system (DUMB!)
       (single I/O, single CPU, single/64-bit memory)

Now my first instinct is to stick with ICP-Vortex for another
controller in a forthcoming system.  The new system will use, if I
can get ahold of one, the Tyan S1867DLUAN mainboard with the
ServerWorks ServerSet IIIHE (or WS?) chipset.  It's a
dual-processor, dual/128-bit memory bus, three-way I/O (one is
64-bit x 66MHz, another 64-bit x 33MHz, plus a legacy 32-bit x
33MHz channel for on-board SCSI/Net/Audio) not including the
AGP-Pro slot (which I could care less about).  As such, I'm putting
this sucker on its own, dedicated PCI channel (64-bit, 33 or 66MHz,
depending on its support for the speed), separate from the Gigabit
controller (I think the NetGear FA620 is a 64-bit x 66MHz PCI card,
not sure -- also, anyone use these suckers with Linux yet? ;-).  I
already have a colleague with one of these mainboards who says
Linux seems to support all the capabilities (seems fully Intel APIO
standard -- ServerWorks, formerly Reliant Computer Corporation,
has a cross-license agreement with Intel, so no "incompatibilities,"
hopefully ;-).

One site that talks about some of the SCSI controllers available
for RAID is NetExpress, at this URL
(http://www.tdl.com/~netex/controllers/controllers.html).  It is
only slightly dated, and does a good job of covering most of the
latest controllers.  They seem to promote the use of PCI RAID
controllers over standalone, OS-independent RAID subsystems
(connected to any SCSI card, since it looks like "one big disk"),
from a performance standpoint.  This would prevent me from using
FreeBSD, which I was considering for proven, stable NFS v3 server
support (God I hope the new 2.4 kernel is out by August with solid
NFS v3 support) for performance reasons as only a few, older PCI
RAID controllers are supported.

Anyhoo, NetExpress' opinion is that the new 233MHz SA 110
(StrongArm) powered Mylex 1100 controllers are lightning fast and
recommended over other i960 powered controllers (usually only
33-100MHz chips) from other vendors (as well as Mylex itself).  Now
the Mylex driver is only a block driver, not a nice generic driver
(like the ICP-Vortex), but that can translate into even increased
performance.  Since I'm interested in maximum performance
anyway, I'll probably just use the on-board 53c896 Ultra2
controller on the S1867DLUAN for the tape autoloader/backup and
DVD-RAM drives.  Not sure if the inter-RAID/SCSI communication will
hurt my performance, although I could always put another SCSI card
on the same PCI channel to minimize it(?).

Anyhoo, back to the Mylex cards, it looks like they have a newer
product, the 2000 series, that has Ultra160 support (I'm probably
going to go with the Seagate 10K 73GB Ultra160 drives).  Although
it uses the same chip and design, it seems the firmware isn't
totally supported by the current Mylex 960/1100 driver yet.  Anyone
know the status of this (I joined the DAC960 announcement list)? 
Even Mylex says the 2000 is "Linux-compatible" on the product page
(but does NOT seem to provide the drivers themselves).  The 64MB
Mylex 2000 board is ~$2K on the street, and may be upgradable to
256MB of cache (not sure, trying to confirm).

I guess that's all I know right now.  Understand that I need
the maximum performance possible which limits my choices (and seems
to preclude the use of a non-PCI RAID solution).  This is first and
foremost, a serious data pushing fileserver (and not just an
Internet/Intranet server), that will move Terabytes of data around
the local network a day.

Anybody's thoughts?  Recommendations?

Thanx in advance ...

-- TheBS

 Bryan "TheBS" Smith -- Engineer, IT Professional and Hacker
      E-mail:  mailto:thebs at theseus.com,b.j.smith at ieee.org
  Disclaimer:  http://www.SmithConcepts.com/legal.html
  TheBS ... Serving E-mail filters to /dev/null since 1989

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