dkstat(1)

NAME
     dkstat - report disk I/O statistics

SYNOPSIS
     dkstat [-h host] [-L] [-f {r|t|s}] [-r] [-w] [-n ndisks] [-c] [-a] [-i
     devspec[,devspec ...]]  [-x devspec[,devspec ...]]  [interval [repeat]]

TYPICAL USAGE
     To monitor I/O rates on all disks every 5 seconds

               dkstat

     To continuously display a table of disks on the host "babylon", use the
     following command;

               dkstat -c -ft -h babylon

DESCRIPTION
     dkstat reports physical disk I/O statistics.  The default report shows
     the average physical I/O rate (requests per second, or IOPS) to each disk
     during the sample interval (default 5 seconds).

     The options to dkstat are as follows;

     -?   Output usage information.

     -h host
          Report for the host host, which must be running pmcd(1).  The
          default is to report for the local host.

     -L   Report for the local host and by-pass pmcd(1).  This option is
          mutually exclusive with the -h option and is the default if pmcd(1)
          is not running.  In either case root privileges are required to by-
          pass pmcd(1) and retrieve the desired metrics directly.

     -c   Invokes continuous mode, using a curses(3) display. This is most
          useful with the "sorted" (-fs) and "table" (-ft) display formats.

     -f {r|t|s}
          Selects the report format as follows:

          -fr  selects ``row'' format (one column per drive).  The report is
               sorted on drive name across the page.  This is the default
               display format.

          -ft  selects ``table'' format (one line per controller).  The report
               is sorted on controller name down the page and by drive unit
               number across the page.
               For SCSI devices with non-zero Logical Unit Numbers (LUNs) all
               devices for a single SCSI target address appear in a the same
               row, sorted by LUN.  Down the page, rows are sorted by SCSI
               target within controller.
          -fs  selects ``sorted'' format (one drive per line).  The report is
               sorted for the most active drive, depending on the -r and -w
               flags.  If neither -r or -w are given, the report is sorted on
               total number of I/Os (reads plus writes).  The -n option
               restricts the report to the ndisks most active disks (default
               22).  The %Busy column in the output is the percentage of time
               during the interval that the drive was active.  The MeanST
               column in the output is the average service time of all
               requests which completed during the interval (in units of
               milliseconds).

     -r   Only report reads from each drive.  The default is to sum reads and
          writes.  The -fs style report will be sorted for the drives which
          perform the most read I/Os per second.

     -w   Only report writes to each drive.  The -fs style report will be
          sorted for the drives which perform the most write I/Os per second.

     -rw  Report both reads and writes to each drive.  If neither -r or -w are
          given, then report total I/Os (reads plus writes).

     interval [repeats]
          Specifies the interval in seconds between successive reports
          (default 5 seconds) and the number of intervals to report (default
          is to repeat forever).  All statistics are averaged over the
          interval.

DEVICE SELECTION
     The -a flag (default) causes all drives and controllers to be reported
     (depending on the report format).  This may be modified by the -i option
     to include only some drives and exclude all others, or by the -x option
     to exclude some drives and include all others.

     The argument to the -i or -x option is a comma separated list (without
     spaces before or after each comma) of device specifiers (devspec).  A
     devspec is a string of characters that might reasonably be expected to be
     the prefix for the names (as report via -I) of one or more devices.

     Examples;

     dks1d6l3       SCSI controller 1, target 6, LUN 3.

     dks0d1         SCSI controller 0, target 1, all LUNs.

     dks4           All drives on SCSI controller 4.

     dks6,dks0d3    All drives on SCSI controller 6 and SCSI target 3 on SCSI
                    controller 0.

SEE ALSO
     pmcd(1), sar(1), sadc(1), gr_top(1), osview(1) and gr_osview(1).