iotop(1) USER COMMANDS iotop(1)
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 com-
pletion (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 direc-
tory. The DTraceToolkit docs may include full worked examples with ver-
bose 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(1)
Mac OS X 10.6 - Generated Thu Sep 17 20:07:55 CDT 2009