{{tag>[multipath centos]}}

=====multipathd CentOS=====
Find wwid
  /lib/udev/scsi_id --whitelisted --device=/dev/sda

Edit /etc/multipath.conf
<code>
defaults {
        user_friendly_names yes
}

blacklist {
        wwid 0000000013130933827B #local SSD
        wwid 00000000131309339304 #local SSD
}

blacklist_exceptions {
        wwid "3600140518cc905dd946fd3912d9c1dd2" #vmshell
        wwid "36001405e4b5224eda4c9d33ebd87dad4" #vmmonitor
        wwid "36001405f41a583adfafdd3fd3d8160d9" #vmweb1
}

multipaths {
        multipath {
                wwid                    3600140518cc905dd946fd3912d9c1dd2
                alias                   vmshell
                path_grouping_policy    multibus
        }
        multipath {
                wwid                    36001405e4b5224eda4c9d33ebd87dad4
                alias                   vmmonitor
                path_grouping_policy    multibus
        }

        multipath {
                wwid                    36001405f41a583adfafdd3fd3d8160d9
                alias                   vmweb1
                path_grouping_policy    multibus
        }


}
</code>

Reload multipathd after change
  * edit /etc/multipath.conf
<code>
    service multipathd reload
    multipath -F   # flush unused device maps
    multipath -d   # dry run
    multipath -v2  # print all info
</code>

Show status
  multipath -ll

Example output
<code>
vmmonitor (36001405e4b5224eda4c9d33ebd87dad4) dm-6 SYNOLOGY,iSCSI Storage
size=32G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
  |- 6:0:0:1 sde 8:64  active ready running
  `- 7:0:0:1 sdf 8:80  active ready running
vmshell (3600140518cc905dd946fd3912d9c1dd2) dm-3 SYNOLOGY,iSCSI Storage
size=32G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
  |- 6:0:0:0 sdc 8:32  active ready running
  `- 7:0:0:0 sdd 8:48  active ready running
vmweb1 (36001405f41a583adfafdd3fd3d8160d9) dm-4 SYNOLOGY,iSCSI Storage
size=64G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
  |- 6:0:0:2 sdg 8:96  active ready running
  `- 7:0:0:2 sdh 8:112 active ready running
</code>
</code>