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diff --git a/Examples/iotop_example.txt b/Examples/iotop_example.txt new file mode 100644 index 000000000000..8cf55c189ba3 --- /dev/null +++ b/Examples/iotop_example.txt @@ -0,0 +1,142 @@ +The following are demonstrations of the iotop program, + + +Here we run iotop with the -C option to not clear the screen, but instead +provide a scrolling output, + + # iotop -C + Tracing... Please wait. + 2005 Jul 16 00:34:40, load: 1.21, disk_r: 12891 KB, disk_w: 1087 KB + + UID PID PPID CMD DEVICE MAJ MIN D BYTES + 0 3 0 fsflush cmdk0 102 4 W 512 + 0 3 0 fsflush cmdk0 102 0 W 11776 + 0 27751 20320 tar cmdk0 102 16 W 23040 + 0 3 0 fsflush cmdk0 102 0 R 73728 + 0 0 0 sched cmdk0 102 0 R 548864 + 0 0 0 sched cmdk0 102 0 W 1078272 + 0 27751 20320 tar cmdk0 102 16 R 1514496 + 0 27751 20320 tar cmdk0 102 3 R 11767808 + + 2005 Jul 16 00:34:45, load: 1.23, disk_r: 83849 KB, disk_w: 488 KB + + UID PID PPID CMD DEVICE MAJ MIN D BYTES + 0 0 0 sched cmdk0 102 4 W 1536 + 0 0 0 sched cmdk0 102 0 R 131072 + 0 27752 20320 find cmdk0 102 0 R 262144 + 0 0 0 sched cmdk0 102 0 W 498176 + 0 27751 20320 tar cmdk0 102 3 R 11780096 + 0 27751 20320 tar cmdk0 102 5 R 29745152 + 0 27751 20320 tar cmdk0 102 4 R 47203328 + + 2005 Jul 16 00:34:50, load: 1.25, disk_r: 22394 KB, disk_w: 2 KB + + UID PID PPID CMD DEVICE MAJ MIN D BYTES + 0 27752 20320 find cmdk0 102 0 W 2048 + 0 0 0 sched cmdk0 102 0 R 16384 + 0 321 1 automountd cmdk0 102 0 R 22528 + 0 27752 20320 find cmdk0 102 0 R 1462272 + 0 27751 20320 tar cmdk0 102 5 R 17465344 + +In the above output, we can see a tar command is reading from the cmdk0 +disk, from several different slices (different minor numbers), on the last +report focusing on 102,5 (an "ls -lL" in /dev/dsk can explain the number to +slice mappings). + +The disk_r and disk_w values give a summary of the overall activity in +bytes. + + + +Bytes can be used as a yardstick to determine which process is keeping the +disks busy, however either of the delta times available from iotop would +be more accurate (as they take into account whether the activity is random +or sequential). + + # iotop -Co + Tracing... Please wait. + 2005 Jul 16 00:39:03, load: 1.10, disk_r: 5302 KB, disk_w: 20 KB + + UID PID PPID CMD DEVICE MAJ MIN D DISKTIME + 0 0 0 sched cmdk0 102 0 W 532 + 0 0 0 sched cmdk0 102 0 R 245398 + 0 27758 20320 find cmdk0 102 0 R 3094794 + + 2005 Jul 16 00:39:08, load: 1.14, disk_r: 5268 KB, disk_w: 273 KB + + UID PID PPID CMD DEVICE MAJ MIN D DISKTIME + 0 3 0 fsflush cmdk0 102 0 W 2834 + 0 0 0 sched cmdk0 102 0 W 263527 + 0 0 0 sched cmdk0 102 0 R 285015 + 0 3 0 fsflush cmdk0 102 0 R 519187 + 0 27758 20320 find cmdk0 102 0 R 2429232 + + 2005 Jul 16 00:39:13, load: 1.16, disk_r: 602 KB, disk_w: 1238 KB + + UID PID PPID CMD DEVICE MAJ MIN D DISKTIME + 0 3 0 fsflush cmdk0 102 4 W 200 + 0 3 0 fsflush cmdk0 102 6 W 260 + 0 3 0 fsflush cmdk0 102 0 W 883 + 0 27758 20320 find cmdk0 102 0 R 55686 + 0 3 0 fsflush cmdk0 102 0 R 317508 + 0 0 0 sched cmdk0 102 0 R 320195 + 0 0 0 sched cmdk0 102 0 W 571084 + [...] + +The disk time is in microseconds. In the first sample, we can see the find +command caused a total of 3.094 seconds of disk time - the duration of the +samples here is 5 seconds (the default), so it would be fair to say that +the find command is keeping the disk 60% busy. + + + +A new option for iotop is to print percents "-P" which are based on disk +I/O times, and hense are a fair measurementt of what is keeping the disks +busy. + + # iotop -PC 1 + Tracing... Please wait. + 2005 Nov 18 15:26:14, load: 0.24, disk_r: 13176 KB, disk_w: 0 KB + + UID PID PPID CMD DEVICE MAJ MIN D %I/O + 0 2215 1663 bart cmdk0 102 0 R 85 + + 2005 Nov 18 15:26:15, load: 0.25, disk_r: 5263 KB, disk_w: 0 KB + + UID PID PPID CMD DEVICE MAJ MIN D %I/O + 0 2214 1663 find cmdk0 102 0 R 15 + 0 2215 1663 bart cmdk0 102 0 R 67 + + 2005 Nov 18 15:26:16, load: 0.25, disk_r: 8724 KB, disk_w: 0 KB + + UID PID PPID CMD DEVICE MAJ MIN D %I/O + 0 2214 1663 find cmdk0 102 0 R 10 + 0 2215 1663 bart cmdk0 102 0 R 71 + + 2005 Nov 18 15:26:17, load: 0.25, disk_r: 7528 KB, disk_w: 0 KB + + UID PID PPID CMD DEVICE MAJ MIN D %I/O + 0 2214 1663 find cmdk0 102 0 R 0 + 0 2215 1663 bart cmdk0 102 0 R 85 + + 2005 Nov 18 15:26:18, load: 0.26, disk_r: 11389 KB, disk_w: 0 KB + + UID PID PPID CMD DEVICE MAJ MIN D %I/O + 0 2214 1663 find cmdk0 102 0 R 2 + 0 2215 1663 bart cmdk0 102 0 R 80 + + 2005 Nov 18 15:26:19, load: 0.26, disk_r: 22109 KB, disk_w: 0 KB + + UID PID PPID CMD DEVICE MAJ MIN D %I/O + 0 2215 1663 bart cmdk0 102 0 R 76 + + ^C + +In the above output, bart and find jostle for disk access as they create +a database of file checksums. The command was, + + find / | bart create -I > /dev/null + +Note that the %I/O is in terms of 1 disk. A %I/O of say 200 is allowed - it +would mean that effectively 2 disks were at 100%, or 4 disks at 50%, etc. + |