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Date:      Tue, 21 Aug 2001 20:58:01 -0400
From:      "Brian" <ircd@wrath.com>
To:        <freebsd-hardware@freebsd.org>
Cc:        <nicole@unixgirl.com>
Subject:   Re: 3ware stuff not ready for heavy duty useage-followup
Message-ID:  <005101c12aa5$7dd36160$0201a8c0@fear.wrath.net>
References:  <XFMail.010821164825.nicole@unixgirl.com> <03d801c12a9e$bab359c0$6601a8c0@elitists.org>

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----- Original Message -----
From: "F. Even" <freebsdlists@elitists.org>
To: "Hodge Podge" <nicole@unixgirl.com>; "Michael VanLoon"
<MichaelV@EDIFECS.COM>
Cc: <freebsd-hardware@FreeBSD.ORG>; <mike.wentz@3ware.com>
Sent: Tuesday, August 21, 2001 8:09 PM
Subject: Re: 3ware stuff not ready for heavy duty useage-followup


> Who sells systems w/ that many disks that is anemically underpowered?  I
> have not seen them a'plenty.  At least not without dual/redundant PS's.  I
> can't fathom running that many devs. on a 300W PS, but it is probably a
> stretch even on a lone 400W, esp. if it has a lot of other devices, or a
> higher clocked chip w/ mounds of memory, those are all pieces that need
> power too.  You are now talking about 400W, but you had mentioned trying
> this on a 300W before also...which is a ridiculous notion.
>
> I have a hard time believing that you have tossed SCSI systems together w/
8
> drives on them and functioning peripherals, on a 300W PS.  If it worked
> great for you, well, great.  Lucky.  Don't count on that as being a good
> practice though.  Fire up an old AT PS to just handle a few of the drives,
> and see if that doesn't help out.

I admit to being a dumb college kid.

OK, the most energy I've ever seen a drive take is when it's powering up
(common sense).  I can't remember seeing a drive that required more than 3
amps to power up.  12v x 3a = 36 watts.  A general rule of thumb is that the
read/write power is half of that that takes to spin the disk up.  So let's
see, that would be 18 watts.

8 disks x 36 watts/disk ~ = 290 watts.  So, she should be definitely safe
with a 400 watt power supply.  It should very much definitely handle it when
running.

Now, I've got a crappy 235watt power supply.  It handles my six drives, my
dual katmai p3-550's, a pair of dual fan cpu fans, and three fans.  Sure,
you can attempt to ridicule me for doing such things, but I shall ridicule
you for being impractical.


So I've got a question for Nicole since I haven't been watching the thread
as closely as I should.  Are the drives completely and utterly dead?  Do
they work as standalones in another machine?  Do they stay spinning or do
they just repeatedly spin up and down?  I imagine you'd know that if they
don't spin chances are the feet welded to the disk and heat got them and I
remember that you were quite sure heat was not a factor.  If you can't get
them to work with a BSD machine and they do stay spun up, try sticking them
in a 32bit windows machine and format them with NTFS4 or NTFS5 (it works
sometimes, I haven't got the foggiest idea why).  Can you run diagnostics on
the disk with the software that the manufacturer of the disk supplies?

Is there a cabling problem?  I assume that all the cables are 80 conductor.
What gauge wire are they?  If they're smaller than 24 gauge (number greater
than 24) somebody should get a firm talking-to.  If they really are longer
than 18" (it seems like you said they were 36"), then the ribbon should be
22 gauge or better.  Are any of the conductors broken on the cable?  I
usually see them broken at one of the connectors on the drive end.  This has
been guilty of killing two of my Maxtor drives.

> Frank

-Brian


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