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)