Storage Foundation 7.4.1 Administrator's Guide - Linux

Gathering and displaying I/O statistics

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

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.

To enable the gathering of statistics, enter this command:

# vxdmpadm iostat start [memory=size]

The memory attribute limits 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 reset the I/O counters to zero, use this command:

# vxdmpadm iostat reset

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

# vxdmpadm iostat show {filter} [interval=seconds [count=N]]

The above command displays I/O statistics for the devices specified by the filter. The filter is one of the following:

Use the interval and count attributes 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.

DMP also provides a groupby option to display cumulative I/O statistics, aggregated by the specified criteria.

See Displaying cumulative I/O statistics.

To disable the gathering of statistics, enter this command:

# vxdmpadm iostat stop