From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tore Anderson Subject: Re: defining paths with DDN 8500 Date: Thu, 13 Sep 2007 10:33:11 +0200 Message-ID: <46E8F5C7.6050005@linpro.no> References: <43123.80742.qm@web51104.mail.re2.yahoo.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <43123.80742.qm@web51104.mail.re2.yahoo.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids * Mike White > I'm working with the multipathing package and a DDN 8500. I've been > able to successfully configure failover and failback. The system is > configured as such: > qla_port_1 ---- ctrl A port 4 ---- LUN 3 (LUN 7) > qla_port_2 ---- ctrl B port 4 ---- LUN 7 (LUN 3) > > Where LUN 3 is on a dedicated port to qla_port_1 and qla_port_2 is > dedicated to LUN 7. > > The problem that I'm having is all the traffic is going through > qla_port_1, qla_port_2 appears to be sitting idle until a failover. > > To compensate, I've been using dmsetup to force the qla_port_2 ---- > LUN 7 path. > > Is there a better way than using dmsetup to do this? multipath isn't > an option, as it negatively impacts performance. Sounds like you're in need of a prio_callout. I'm not familiar with your hardware so I don't know if there's already one available, if not, make a simple script that for example prints "2" for the paths you want to prefer and "1" for the ones you want to use as backups. Then set path_grouping_policy to "failover". You might also want to set failback to "immediate". Regards -- Tore Anderson