InfoScale™ 9.0 Dynamic Multi-Pathing Administrator's Guide - AIX

Examples of using the vxdmpadm iostat command

Dynamic Multi-Pathing (DMP) enables you to gather and display I/O statistics with the vxdmpadm iostat command. This section provides 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 the kilobytes read and written, on all paths.

# vxdmpadm -u k iostat show all
                     cpu usage = 7952us    per cpu memory = 8192b
               OPERATIONS           BYTES             AVG TIME(ms)
PATHNAME   READS     WRITES     READS     WRITES     READS   WRITES
hdisk10       87          0     44544k         0      0.00     0.00
hdisk16        0          0         0          0      0.00     0.00
hdisk11       87          0     44544k         0      0.00     0.00
hdisk17        0          0         0          0      0.00     0.00
hdisk12       87          0     44544k         0      0.00     0.00
hdisk18        0          0         0          0      0.00     0.00
hdisk13       87          0     44544k         0      0.00     0.00
hdisk19        0          0         0          0      0.00     0.00
hdisk14       87          0     44544k         0      0.00     0.00
hdisk20        0          0         0          0      0.00     0.00
hdisk15       87          0     44544k         0      0.00     0.00
hdisk21        0          0         0          0      0.00     0.00

The following command changes the amount of memory that vxdmpadm can use to accumulate the statistics:

# vxdmpadm iostat start memory=4096

The displayed statistics can be filtered by path name, DMP node name, and enclosure name (note that the per-CPU memory has changed following the previous command):

# vxdmpadm -u k iostat show pathname=hdisk17
                      cpu usage = 8132us    per cpu memory = 4096b
                OPERATIONS             BYTES           AVG TIME(ms)
PATHNAME    READS     WRITES      READS     WRITES    READS   WRITES
hdisk17         0          0          0          0     0.00     0.00

# vxdmpadm -u k iostat show dmpnodename=hdisk10
                     cpu usage = 8501us    per cpu memory = 4096b
               OPERATIONS             BYTES            AVG  TIME(ms)
PATHNAME   READS     WRITES      READS     WRITES     READS   WRITES
hdisk10     1088          0    557056k          0      0.00     0.00

# vxdmpadm -u k iostat show enclosure=Disk
                     cpu usage = 8626us    per cpu memory = 4096b
               OPERATIONS            BYTES            AVG TIME(ms)
PATHNAME   READS     WRITES      READS     WRITES     READS   WRITES
hdisk10     1088          0    557056k          0      0.00     0.00

You can also specify the number of times to display the statistics and the time interval. Here the incremental statistics for a path are displayed twice with a 2-second interval:

# vxdmpadm iostat show pathname=hdisk17 interval=2 count=2
                      cpu usage = 719us    per cpu memory = 49152b
               OPERATIONS            BLOCKS          AVG TIME(ms)
PATHNAME   READS    WRITES     READS    WRITES     READS    WRITES
hdisk17    0        0          0         0          0.00      0.00

hdisk17    0        0          0         0          0.00      0.00