Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

Displaying the status of the DMP path restoration thread
Use the following command to display the status of the automatic path restoration
kernel thread, its polling interval, and the policy that it uses to check the condition
of paths:
# vxdmpadm stat restored
This produces output such as the following:
The number of daemons running : 1
The interval of daemon: 300
The policy of daemon: check_disabled
Displaying information about the DMP error-handling thread
To display information about the kernel thread that handles DMP errors, use the
following command:
# vxdmpadm stat errord
One daemon should be shown as running.
Configuring array policy modules
An array policy module (APM) is a dynamically loadable kernel module (plug-in
for DMP) for use in conjunction with an array. An APM defines array-specific
procedures and commands to:
■ Select an I/O path when multiple paths to a disk within the array are available.
■ Select the path failover mechanism.
■ Select the alternate path in the case of a path failure.
■ Put a path change into effect.
■ Respond to SCSI reservation or release requests.
DMP supplies default procedures for these functions when an array is registered.
An APM may modify some or all of the existing procedures that are provided by
DMP or by another version of the APM.
You can use the following command to display all the APMs that are configured
for a system:
# vxdmpadm listapm all
The output from this command includes the file name of each module, the
supported array type, the APM name, the APM version, and whether the module
Administering Dynamic Multi-Pathing
Administering DMP using vxdmpadm
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