Red Hat Training

A Red Hat training course is available for Red Hat Enterprise Linux

5.7. Multipath Command Output

When you create, modify, or list a multipath device, you get a display of the current device setup. The format is as follows.
For each multipath device:
 action_if_any: alias (wwid_if_different_from_alias) dm_device_name_if_known vendor,product size=size features='features' hwhandler='hardware_handler' wp=write_permission_if_known 
For each path group:
-+- policy='scheduling_policy' prio=prio_if_known status=path_group_status_if_known
For each path:
 `- host:channel:id:lun devnode major:minor dm_status_if_known path_status online_status
For example, the output of a multipath command might appear as follows:
3600d0230000000000e13955cc3757800 dm-1 WINSYS,SF2372
size=269G features='0' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=1 status=active
| `- 6:0:0:0 sdb 8:16  active ready  running
`-+- policy='round-robin 0' prio=1 status=enabled
  `- 7:0:0:0 sdf 8:80  active ready  running
If the path is up and ready for I/O, the status of the path is ready or ghost. If the path is down, the status is faulty or shaky. The path status is updated periodically by the multipathd daemon based on the polling interval defined in the /etc/multipath.conf file.
The dm status is similar to the path status, but from the kernel's point of view. The dm status has two states: failed, which is analogous to faulty, and active which covers all other path states. Occasionally, the path state and the dm state of a device will temporarily not agree.
The possible values for online_status are running and offline. A status of offline means that this SCSI device has been disabled.


When a multipath device is being created or modified, the path group status, the dm device name, the write permissions, and the dm status are not known. Also, the features are not always correct.