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Multipath Queries with multipath Command

For each multipath device:

action_if_any: alias (wwid_if_different_from_alias) [size][features][hardware_handler]

For each path group:

\_ scheduling_policy [path_group_priority_if_known] [path_group_status_if_known]

For each path:

\_ host:channel:id:lun devnode major:minor [path_status] [dm_status_if_known]

For example, the output of a multipath command might appear as follows:

mpath1 (3600d0230003228bc000339414edb8101) [size=10 GB][features="0"][hwhandler="0"]

\_ round-robin 0 [prio=1][active]

\_ 2:0:0:6 sdb 8:16 [active][ready]

\_ round-robin 0 [prio=1][enabled]

\_ 3:0:0:6 sdc 8:64 [active][ready]

If the path is up and ready for I/O, the status of the path is ready or active. If the path is down, the

status is faulty or failed. 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.

Note

When a multipath device is being created or modified, the path group status and the dm status

are not known. Also, the features are not always correct. When a multipath device is being listed,

the path group priority is not known.

5.6. Multipath Queries with multipath Command

You can use the -l and -ll options of the multipath command to display the current multipath

configuration. The -l option displays multipath topology gathered from information in sysfs and

the device mapper. The -ll option displays the information the -l displays in addition to all other

available components of the system.

When displaying the multipath configuration, there are three verbosity levels you can specify with the

-v option of the multipath command. Specifying -v0 yields no output. Specifying -v1 outputs the

created or updated multipath names only, which you can then feed to other tools such as kpartx.

Specifying -v2 prints all detected paths, multipaths, and device maps.

The following example shows the output of a multipath -l command.

# multipath -l

1 2 ... 32 33 34 35 36 37 38 39 40 41 42 43 44

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Red Hat GNBD WITH GLOBAL FILE SYSTEM IN RHEL 4.5 Guida di Installazione Pagina 37