By default, DMP is configured with I/O throttling turned off for all paths. To display the current settings for I/O throttling that are applied to the paths to an enclosure, array name or array type, use the vxdmpadm getattr command.
If enabled, I/O throttling imposes a small overhead on CPU and memory usage because of the activity of the statistics-gathering daemon. If I/O throttling is disabled, the daemon no longer collects statistics, and remains inactive until I/O throttling is re-enabled.
To turn off I/O throttling, use the following form of the vxdmpadm setattr command:
# vxdmpadm setattr \ {enclosure enc-name|arrayname name|arraytype type} \ recoveryoption=nothrottle
The following example shows how to disable I/O throttling for the paths to the enclosure enc0:
# vxdmpadm setattr enclosure enc0 recoveryoption=nothrottle
The vxdmpadm setattr command can be used to enable I/O throttling on the paths to a specified enclosure, disk array name, or type of array:
# vxdmpadm setattr \ {enclosure enc-name|arrayname name|arraytype type}\ recoveryoption=throttle [iotimeout=seconds]
If the iotimeout attribute is specified, its argument specifies the time in seconds that DMP waits for an outstanding I/O request to succeed before invoking I/O throttling on the path. The default value of iotimeout is 10 seconds. Setting iotimeout to a larger value potentially causes more I/O requests to become queued up in the SCSI driver before I/O throttling is invoked.
The following example sets the value of iotimeout to 60 seconds for the enclosure enc0:
# vxdmpadm setattr enclosure enc0 recoveryoption=throttle \ iotimeout=60
Specify recoveryoption=default to reset I/O throttling to the default settings, as follows:
# vxdmpadm setattr arraytype A/A recoveryoption=default
The above command configures the default behavior, corresponding to recoveryoption=nothrottle. The above command also configures the default behavior for the response to I/O failures.