[NCLUG] Low Cost Terabyte File Server

[Sean Reifschneider]

On Wed, Nov 28, 2001 at 10:22:37AM -0700, Michael Dwyer wrote:
>The FastTrack drivers seem to be pretty lacking, and besides that
>it sounds like it is all software-raid anyway.  I'm still debating
>what to do with it...  Has anyone had any successes with this card?

I did some testing of the FastTrak boards a couple of years ago and found
them lacking.  The controller actually does do the RAID-1, but even with
the "hot swap" enclosures that they sell along with the card as a kit, the
system was not happy with a drive going missing.  It would just lock up.

ESR and I were conversing some about IDE versus SCSI before he published
his recent Ultimate Linux Box article.  The original versions were quite
hard on IDE...  Rick Moen got into the discussion, brining ad hominems to
support his assertions that IDE sucked based on using it back in 1995.

I finally put together a test box using a couple of UW 7200RPM SCSI drives
and a Symbios 875 controller, versus 3 7200RPM IDE drives (the best
hardware I could pull together for running this test).

The IDE solution was roughly a half the cost or less of the SCSI, and
performed at least as well.  At seeking it was only slightly faster (maybe
30%).  At the "per char" I/O, IDE was very slightly faster (5 or 10%).
At Block I/O, IDE was around 3x faster.

One of the often quoted issues with IDE is the CPU utilization.  I found
that when you adjusted for speed, IDE's CPU utilization was roughly the
same as SCSI (meaning that it used 3x more CPU while performing 3x faster,
which isn't unexpected).

I also ran GCC rebuilds (since Eric's article was about building a
developers box), and IDE was roughly the same performance as the SCSI
setup.  Again, slightly faster, but over 34 minutes of build, the
difference was less than a minute.  Rick had been asserting a 5x
performance increase in using SCSI over IDE for large builds).

Sure, you can get "ultimate" performance if you have a bunch of 15KRPM SCSI
drives, but the drives and colling hardware for them are coming close to
the cost of 8 IDE drives and a RAID controller for it.  And the RAID
controller for the SCSI is more...

Sean
-- 
 "Sometimes Omaha can't be avoided."
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Sean Reifschneider, Inimitably Superfluous <jafo at tummy.com>
tummy.com - Linux Consulting since 1995. Qmail, KRUD, Firewalls, Python