Red Hat DEVICE-MAPPER MULTIPATH 5.2, Configuration And Administration Manual

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DM-Multipath Administration and
Troubleshooting
This chapter will provide information on administering DM-Multipath on a running system. It
includes sections on the following topics:
• Multipath Command Output
• Multipath Queries with multipath Command
• Multipath Command Options
• Multipath Queries with dmsetup Command
• Troubleshooting with the multipathd Interactive Console
1. Multipath Command Output
When you create, modify, or list a multipath device, you get a printout of the current device
setup. The format is as follows.
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]
Chapter 5.
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