From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Doug Griswold" Subject: Re: md multipath and failover Date: Thu, 11 Sep 2003 07:07:16 -0400 Sender: linux-raid-owner@vger.kernel.org Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline To: Doug Griswold , lmb@suse.de, linux-raid@vger.kernel.org List-Id: linux-raid.ids Thanks for the info. My next question is I have set the link down timeout in the emulex driver to be 15 seconds but the paths are still not failing over for 5 minutes. Is there a way to get the scsi timeout= s down to 30 seconds? Can I pass anything to the scsi module at boot? If I applied your patch that provides load balancing then I would not have t= o worry about this issue since they are both working already we wouldn't have the timeout issue. Does your patch pick up on the path once it becomes available after losing it? =20 Thanks for the info. Doug=20 >>> Lars Marowsky-Bree 09/11/03 03:45 AM >>> On 2003-09-10T18:55:41, Doug Griswold said: > Alright I got md/multipath to failover with 2 emulex hba's on red hat > advanced server 2.1 kernel version 2.4.9-27enterprise. My next new > problem is that it took five minutes to fail over from when I yanked one > of the fibre channel cables. Where could this timeout come from? I > have tried several times but each time it takes 5 minutes to failover= =2E > Also it won't failback. Any ideas out there. =20 The plain md multipath can't do failback automatically. People's opinio= n on whether that is a good idea do differ ;-) The timeout is the time needed until the damn (sorry) Linux Kernel SCSI layers give up retrying and then pass the error code up to md for handling. You can maybe try tuning some emulex parameters to fix that. If you want load balancing for the md multipath, you could try checking out my patch at ftp://ftp.suse.com/pub/people/lmb/md-mp/ vs 2.4, it add= s some features to md and also makes it quite a bit more robust. Sincerely, Lars Marowsky-Br=E9e --=20 High Availability & Clustering ever tried. ever failed. no matter. SuSE Labs try again. fail again. fail better. Research & Development, SuSE Linux AG -- Samuel Beckett - To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html