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iotop(1m)                                       USER COMMANDS                                      iotop(1m)



NAME
       iotop - display top disk I/O events by process. Uses DTrace.

SYNOPSIS
       iotop [-C] [-D|-o|-P] [-j|-Z] [-d device] [-f filename] [-m mount_point] [-t top] [interval [count]]

DESCRIPTION
       iotop tracks disk I/O by process, and prints a summary report that is refreshed every interval.

       This is measuring disk events that have made it past system caches.

       Since this uses DTrace, only users with root privileges can run this command.

OPTIONS
       -C     don't clear the screen

       -D     print delta times - elapsed, us

       -j     print project ID

       -o     print disk delta times, us

       -P     print %I/O (disk delta times)

       -Z     print zone ID

       -d device
              instance name to snoop (eg, dad0)

       -f filename
              full pathname of file to snoop

       -m mount_point
              mountpoint for filesystem to snoop

       -t top print top number only


EXAMPLES
       Default output, print summary every 5 seconds
              # iotop


       One second samples,
              # iotop 1


       print %I/O (time based),
              # iotop -P


       Snoop events on the root filesystem only,
              # iotop -m /

       Print top 20 lines only,
              # iotop -t 20

       Print 12 x 5 second samples, scrolling,
              # iotop -C 5 12


FIELDS
       UID    user ID

       PID    process ID

       PPID   parent process ID

       PROJ   project ID

       ZONE   zone ID

       CMD    command name for the process

       DEVICE device name

       MAJ    device major number

       MIN    device minor number

       D      direction, Read or Write

       BYTES  total size of operations, bytes

       ELAPSED
              total  elapsed  times  from  request to completion, us (this is the elapsed time from the disk
              request (strategy) to the disk completion (iodone))

       DISKTIME
              total times for disk to complete request, us (this is the time for the disk to  complete  that
              event  since  it's last event (time between iodones), or, the time to the strategy if the disk
              had been idle)

       %I/O   percent disk I/O, based on time (DISKTIME)

       load   1 minute load average

       disk_r total disk read Kb for sample

       disk_w total disk write Kb for sample


DOCUMENTATION
       See the DTraceToolkit for further documentation under the Docs directory. The DTraceToolkit docs  may
       include full worked examples with verbose descriptions explaining the output.

EXIT
       iotop will run forever until Ctrl-C is hit, or the specified interval is reached.

AUTHOR
       Brendan Gregg [Sydney, Australia]

SEE ALSO
       iosnoop(1M), dtrace(1M)




version 0.75                                    Oct 25, 2005                                       iotop(1m)

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