Networker

Re: [Networker] use of one fibre card for disk and tape access

2007-01-30 06:11:18
Subject: Re: [Networker] use of one fibre card for disk and tape access
From: Will Parsons <w.parsons AT LEEDS.AC DOT UK>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Tue, 30 Jan 2007 11:02:27 +0000
Hi Mark,
We're running Sun servers with Emulex LP9802 HBA'a in this kind of setup, and it's (usually) stable & happy. We started out (in 2003) on Q-logic 2340 cards, but the issue about HBA resets (as Lancy mentions) came to bite us. The actual failures were due to the SAN fabric (Mcdata 3232 switches) sending out RSCN (Register State Change Notifications?) to all connected HBA's when a change occured (host reboot etc). The Q-logic answer to this (and default Emulex behavior) is to re-login to the fabric, which breaks the tape IO stream, but is fine for disk IO.

The emulex cards have an option "USE ADISC", which alters the RSCN behavior so that the HBA does a softer query of the fabric as to what devices it's allowed to see - without breaking your tape IO stream :-)

My master server has two HBA's. They were set up one for disk, one for tape, but the IO required for the tape traffic meant I've had to move half of my tape IO on to the other HBA (shared with the disk access to the /nsr partition). Been like that for a year of so with no problems.

I'm not too sure about sending buckets of backup-to-disk data down the same HBA's, but that more throughput related than expecting errors.

HTH.

Will

mark wragge wrote:
What is the general opinion for use of one fibre card to access SAN attached 
disk and then also using that fibre card for access to SAN attached tape 
devices. I know that such configurations are supported but do they work 
consistently and are they recommended?
Thanks.

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UNIX Support
Information Systems Services
The University of Leeds
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