Networker

Re: [Networker] SCSI problems -- How many drives to a bus?

2004-01-09 16:55:30
Subject: Re: [Networker] SCSI problems -- How many drives to a bus?
From: Tim Mooney <mooney AT DOGBERT.CC.NDSU.NODAK DOT EDU>
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Date: Fri, 9 Jan 2004 15:55:24 -0600
In regard to: Re: [Networker] SCSI problems -- How many drives to a bus?,...:

>Also, just as important as spreading the load across the SCSI buses is
>spreading the PCI load across PCI buses.

Very true, but that can often be difficult to do with Intel hardware,
especially if you also need to install cards in addition to tape I/O
controllers.  Our current Red Hat 7.3 backup server has plenty of RAM
and CPU power, but I'm pretty sure that the problems I've been seeing
(a near complete hang of the system, though SysRq still works so
interrupts are being serviced) relate to I/O issues.

The fact that we're using two 64 bit 66 MHz PCI fiber Gigabit Ethernet cards
and two 100 MHz PCI-X QLA2300 FC cards in a box that wasn't designed with
that much I/O in mind is a big part of the problem.  That we're driving
our traditional SCSI 9710 STK library by hanging it off two FC<->SCSI
routers on our SAN is probably the major part of the problem.

So, those of you with SCSI problems take heart:  At least you don't have
a SAN and FC<->SCSI routers in the mix too!  ;-)  I know, it's little
consolation, but I'm just trying to brighten your day.

Tim
--
Tim Mooney                              mooney AT dogbert.cc.ndsu.NoDak DOT edu
Information Technology Services         (701) 231-1076 (Voice)
Room 242-J6, IACC Building              (701) 231-8541 (Fax)
North Dakota State University, Fargo, ND 58105-5164

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