From mboxrd@z Thu Jan 1 00:00:00 1970 From: gistolero@gmx.de Subject: Re: mpath_ctl observation + some novice questions Date: Thu, 15 Sep 2005 18:31:38 +0200 Message-ID: <4329A1EA.9040203@gmx.de> References: <20050915132538.GA27752@locust.cns.vt.edu> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20050915132538.GA27752@locust.cns.vt.edu> 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 Hi, > Next topic. I'm a real dm novice user. I have not > figured out how to create the disk devices and lvm fs. Is there > a doc on how to do this? My guess is that I need > to map the wwid in multipath.conf. Is this demonstrated > somewhere? Thanks. use a test environment, no production server! startup-configuration: 1.) load dm-mapper and HBA kernel modules 2.) create partitions on each lun (e.g.: lun0 has two paths sda and sdb - "fdisk sda" creates the partitions for sda _and_ sdb) - you have to do this step _before_ creating multipath devices (kpartx in /etc/dev.d/block/multipath.dev reads this partition information) 3.) create /etc/multipath.conf - check multipath.conf.annotated and multipath.conf.synthetic in the multipath-tools tarball - get lun wwid's with "scsi_id -g -u -s /block/sd?" - create a "multipath { ... }" section for each lun (define "wwid" and "alias") - create a "device { ... }" section for your storage (see "TestedEnvironments" located at the multipath-tools homepage) - set "path_grouping_policy" and "prio_callout" (setting "prio_callout" is important. if you choose a wrong value, you will see nothing after starting multipath) 4.) start multipathd (debug with "-d" or "-v4" (syslog)) 5.) run "multipath /dev/sd?" for each sd? device multipath should create device-mapper table entries (see "dmsetup table"), block-device-files in /dev/mapper/ and links in /dev/ for the lun and for each partition e.g.: you have created two partitions and your lun alias is "yellow" (defined in /etc/multipath.conf): # dmsetup table yellow1: ... yellow: ... yellow2: ... # ls /dev/mapper/ yellow yellow1 yellow2 control # ls -F /dev/yellow* /dev/yellow@ /dev/yellow1@ /dev/yellow2@ and check "multipath [-v3] -ll" 6.) create filesystems and mount /dev/yellow1 and /dev/yellow2 you can delete the current configuration with "dmsetup remove yellow2; dmsetup remove yellow1; dmsetup remove yellow" hope that helps simon