红帽全球峰会第 8 章 Troubleshooting DM Multipath
Troubleshoot multipath configuration issues by checking daemon status, queue_if_no_path feature problems, and using the multipathd interactive console for diagnostics.
The following issues may result in a slow or non-functioning multipath configuration:
- The multipath daemon is not running
-
If you find you have trouble implementing a multipath configuration, ensure that the
multipathddaemon is running, as described in Configuring DM Multipath. Themultipathddaemon must be running to use multipathed devices. - Issues with
queue_if_no_pathfeature -
If a multipath device is configured with the
features "1 queue_if_no_path"option, then any process that issues I/O hangs until one or more paths are restored.
Resolve I/O hangs from queue_if_no_path by setting no_path_retry N in /etc/multipath.conf, limiting retries when all paths fail. You can also disable queueing at runtime for specific LUNs to prevent applications from hanging during path outages.
Procedure
Disable queueing:
For a specific device:
# multipathd disablequeueing map deviceFor all devices:
# multipathd disablequeueing mapsAfter you disable queueing, it will remain disabled until you restart or reload
multipathd.
Reset queueing to a previous value:
For a specific device:
# multipathd restorequeueing map deviceFor all devices:
# multipathd restorequeueing maps
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