Gathering and displaying DMP I/O statistics

You can use the vxdmpadm iostat command to gather and display I/O statistics for a specified DMP node, enclosure, path or controller.

To enable the gathering of statistics, enter this command:

# vxdmpadm iostat start [memory=size]

To reset the I/O counters to zero, use this command:

# vxdmpadm iostat reset

The memory attribute can be used to limit the maximum amount of memory that is used to record I/O statistics for each CPU. The default limit is 32k (32 kilobytes) per CPU.

To display the accumulated statistics at regular intervals, use the following command:

# vxdmpadm iostat show {all | ctlr=ctlr-name \
  | dmpnodename=dmp-node  \
  | enclosure=enclr-name [portid=array-portid ] \
  | pathname=path-name |  pwwn=array-port-wwn } \
  [interval=seconds [count=N]]

This command displays I/O statistics for all paths (all), or for a specified controller, DMP node, enclosure, path or port ID. The statistics displayed are the CPU usage and amount of memory per CPU used to accumulate statistics, the number of read and write operations, the number of kilobytes read and written, and the average time in milliseconds per kilobyte that is read or written.

The interval and count attributes may be used to specify the interval in seconds between displaying the I/O statistics, and the number of lines to be displayed. The actual interval may be smaller than the value specified if insufficient memory is available to record the statistics.

To disable the gathering of statistics, enter this command:

# vxdmpadm iostat stop