Red Hat DEVICE-MAPPER MULTIPATH 4.6 Configuration And Administration Manual

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\_ 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 multipathddaemon 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 statushas two states: failed, which is analogous to faulty, and active which covers all other pathstates. Occasionally, the path state and the dm state of a device will temporarily not agree.NoteWhen a multipath device is being created or modified, the path group status andthe dm status are not known. Also, the features are not always correct. When amultipath device is being listed, the path group priority is not known.2. Multipath Queries with multipath CommandYou can use the -l and -ll options of the multipath command to display the current multipathconfiguration. The -l option displays multipath topology gathered from information in sysfs andthe device mapper. The -ll option displays the information the -l displays in addition to allother available components of the system.When displaying the multipath configuration, there are three verbosity levels you can specifywith the -v option of the multipath command. Specifying -v0 yields no output. Specifying -v1outputs the created or updated multipath names only, which you can then feed to other toolssuch as kpartx. Specifying -v2 prints all detected paths, multipaths, and device maps.The following example shows the output of a multipath -l command.# multipath -1mpath1 (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]3. Multipath Command OptionsTable 5.1, “Useful multipath Command Options” describes some options of the multipathcommand that you may find useful.Chapter 5. DM-Multipath Administration and Troubleshooting28