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Date: Sun, 17 Aug 1997 20:02:04 -0700 (PDT)
From: Tom Samplonius <tom@sdf.com>
To: Curt Welch <curt@kcwc.com>
cc: scsi@freebsd.org
Subject: Re: expected performance with DPT RAID-5...
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On Sun, 17 Aug 1997, Curt Welch wrote:

> Tom wrote:
> >  If I have 5 Barracuda 4LP 4GB drive (about 8MB/s raw
> >  read/write) on a single ultra wide channel on a DPT
> >  PM334/UW setup in a RAID-5 array, what kind of
> >  sequentional read/write performance should I expect?
> 
> Don't know what to expect, but I have a similar config.
> 
> I have 5 Quantaum Atlas I 4G (fast wide) drives in a RAID-5
> config on one bus of of PM3334UW/2 and 5 Quantum Viking 4.55G
> (ultra wide) also in a RAID-5 config on the other bus.  The
> system is a 180MHz Pentium Pro with 128MB of memory.  The
> DPT has a full 64MB of cache (non ecc).
> 
> If you want me to run a test and tell you how it performs
> I will.  What type of test would you like to see?

  "cd" to one of the RAID-5 file systems and do a "dd if=/dev/zero
of=testfile bs=64k count=1000".  That will create a file called "testfile"
64MB in length (64k x 1000), and tell you how long it took to write it.

  Then reboot (the only way I know of clearing the FreeBSD file cache, and
the DPT cache), and do a "dd if=testfile bs=64k of=/dev/null" to read the
file back.

  On the write test I get about 3500000 bps, and the write test about
9200000 bps.  These results don't seem very good too me.

> BTW, the system still crashes every few days.  Don't know
> for sure if it's probelms with the system, the DPT or the
> DPT driver - I'm still working on it.  It was very stable
> before installing the DPT and the 10 new drives.
> 
> Curt

Tom