HP Veritas Volume Manager 5.0 -UX 11i v3 manual Gathering and displaying I/O statistics

144

Administering dynamic multipathing (DMP)

Administering DMP using vxdmpadm

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 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 dmpnodename=dmp-node \ enclosure=enclr-namepathname=path-namectlr=ctlr-name} \ [interval=seconds [count=N]]

This command displays I/O statistics for all controllers (all), or for a specified DMP node, enclosure, path 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.

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

Examples of using the vxdmpadm iostat command

The follow is an example session using the vxdmpadm iostat command. The first command enables the gathering of I/O statistics:

#vxdmpadm iostat start

The next command displays the current statistics including the accumulated total numbers of read and write operations and kilobytes read and written, on all paths:

#vxdmpadm iostat show all

		cpu usage = 7952us			per cpu memory = 8192b
	OPERATIONS		KBYTES			AVG TIME(ms)
PATHNAME	READS	WRITES	READS	WRITES		READS	WRITES
c0t0d0	1088	0	557056		0	0.009542	0.000000
c2t118d0	87	0	44544		0	0.001194	0.000000
c3t118d0	0	0	0		0	0.000000	0.000000
c2t122d0	87	0	44544		0	0.007265	0.000000
c3t122d0	0	0	0		0	0.000000	0.000000