Hi,
Next topic. I'm a real dm novice user. I have notfigured 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 demonstratedsomewhere? Thanks.
use a test environment, no production server! startup-configuration: 1.) load dm-mapper and HBA kernel modules2.) 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? devicemultipath 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/yellow2you can delete the current configuration with "dmsetup remove yellow2; dmsetup remove yellow1; dmsetup remove yellow"
hope that helps simon
