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Date:      Fri, 24 Apr 1998 16:50:01 -0700 (PDT)
From:      Tom <tom@sdf.com>
To:        Don Wilde <dwilde1@ibm.net>
Cc:        Remy NONNENMACHER <remy@synx.com>, don@partsnow.com, freebsd-advocacy@FreeBSD.ORG, freebsd-hardware@FreeBSD.ORG
Subject:   Re: *** Real Action Item: SPECweb
Message-ID:  <Pine.BSF.3.95q.980424164549.11519A-100000@misery.sdf.com>
In-Reply-To: <3540E0AF.C3B5C576@ibm.net>

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On Fri, 24 Apr 1998, Don Wilde wrote:

> Tom wrote:
> 
> >   Better off using the hardware RAID0 in a DPT PM334UW.  It also has 64MB
> > of write-back cache so, it can re-order i/o to be more efficient.
> > 
> >   Also, using only tiny bit of each hard drive improves drive level
> > caching.  Most drives have only a 1MB cache.
> 
> I have a friend at Winchester Systems who's trying to sell me a SCSI-3
> RAID box, and I think they'd be willing to let us borrow one for a test
> in return for favorable mention http://www.winsys.com. He says they work
> with fast differential 2944's as host cards. Is the DPT faster with the
> direct bus connection? No SCSI at all?

  SCSI-to-SCSI RAID boxes impose latency.  Plus the most you can get out a
single array is 40MB/s (or 80MB/s with Ultra2).

  DPT still uses SCSI, but only to talk to the drives.  It talks to the
host via PCI (132MB/s), not SCSI that the stand-alone RAID boxes use.

> Does anybody have experience with these new Compact PCI chassis that
> have 8 PCI slots? An obvious bottleneck for anything we can do is going
> to be the chassis limitation on most of 4 PCI. I believe the Compaq
> Proliant is EISA.

  Proliant is a series of machines with many different models.

  Don't buy anything Compaq.

  Buy a server class motherboard from Intel.  I think they make some nice
one with lots of PCI slots.

Tom


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