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

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

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

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.

don't clear the screen
print delta times - elapsed, us
print project ID
print disk delta times, us
print %I/O (disk delta times)
print zone ID
instance name to snoop (eg, dad0)
full pathname of file to snoop
mountpoint for filesystem to snoop
print top number only

# iotop
# iotop 1
# iotop -P
# iotop -m /
# iotop -t 20
# iotop -C 5 12

user ID
process ID
parent process ID
project ID
zone ID
command name for the process
device name
device major number
device minor number
direction, Read or Write
total size of operations, bytes
total elapsed times from request to completion, us (this is the elapsed time from the disk request (strategy) to the disk completion (iodone))
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)
percent disk I/O, based on time (DISKTIME)
1 minute load average
total disk read Kb for sample
total disk write Kb for sample

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

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

Brendan Gregg [Sydney, Australia]

iosnoop(1M), dtrace(1M)

October 25, 2005 version 0.75