From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josef Whiter Subject: Re: Multipathing using device mapper howto? Date: Fri, 28 Oct 2005 16:36:20 -0400 Message-ID: <43628BC4.5010909@redhat.com> References: <43628C96.2090605@trilegiant.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <43628C96.2090605@trilegiant.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 Bruen, Mark wrote: > I'm just beginning to look at device mapper to multipath SAN luns. > I've been searching for some time and can't find a simple reference on > how to create the multipathed devices from the same luns presented to > two or more HBA paths. Is there a source for that information? > Thanks. > -Mark > > -- > dm-devel mailing list > dm-devel@redhat.com > https://www.redhat.com/mailman/listinfo/dm-devel I don't know of any external sources, but the quick and dirty way is to first fdisk your /dev/sd devices, and then edit your /etc/multipath.conf file and comment out hte lines devnode_blacklist { devnode "*" } and then uncomment out the lines defaults { multipath_tool "/sbin/multipath -v0" udev_dir /dev polling_interval 10 default_selector "round-robin 0" default_path_grouping_policy multibus default_getuid_callout "/sbin/scsi_id -g -u -s /block/%n" default_prio_callout "/bin/true" default_features "0" rr_wmin_io 100 failback immediate } Then reboot, and it should work. You're devices should show up in /dev/dm-#, then all you want to do is do a kpartx -a on /dev/dm-# and it will create a new /dev/dm-#+1 for the partitions (ie if my disk was /dev/dm-0 and i had one partition, and i ran kpartx -a i would get /dev/dm-1. its equivalent of /dev/sda and /dev/sda1). Thank you, Josef -- Josef Whiter, RHCE Global Support Services Red Hat, Inc. 919-754-3700 x44429