The following is a demonstration of the dvmstat program, Here we run dvmstat to monitor all processes called "find". In another window, a "find /" command is run, # dvmstat -n find re maj mf fr epi epo api apo fpi fpo sy 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6336 0 372 0 0 0 0 0 0 0 22255 1624 0 0 0 0 0 0 0 0 0 5497 2292 0 0 0 0 0 0 0 0 0 7715 13064 0 0 0 0 0 0 0 0 0 43998 7972 168 0 0 0 0 0 0 168 0 38361 468 636 0 0 0 0 0 0 636 0 13774 376 588 0 0 0 0 0 0 588 0 10723 80 636 0 0 0 0 0 0 656 0 11078 48 772 0 0 0 0 0 0 812 0 9841 16 1028 0 0 0 0 0 0 1056 0 10752 0 1712 0 0 0 0 0 0 1740 0 12176 4 1224 0 0 0 0 0 0 1236 0 9024 The output above is spectacular! When the find command is first run, it begins be reading data from the file cache, as indicated by the "re" reclaims, and a lack of "fpi" filesystem page ins. Eventually the find command travels to places which are not cached, we can see the "re" value drops, and both the "maj" major faults and "fpi" values increase. This transition from cache hits to file system activity is very clear from the above output. Here we run a dvmstat to examine the PID 3778, # dvmstat -p 3778 re maj mf fr epi epo api apo fpi fpo sy 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 24 28 0 0 0 0 0 0 28 0 109 4 148 16 0 0 0 0 0 148 0 1883 16 412 384 0 0 0 0 0 412 0 21019 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 221 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 84 0 0 0 0 0 0 0 0 0 0 0 Here we can see the statistics for that process only. The following runs the date command through dvmstat, # dvmstat date Sun Jun 12 17:44:24 EST 2005 re maj mf fr epi epo api apo fpi fpo sy 16 0 208 0 0 0 0 0 0 0 38 The values above are for the date command only. Now we run dvmstat on a tar command. Here we tar around 50Mb of files, so the command takes around 20 seconds to complete, # dvmstat tar cf backup.tar DTrace re maj mf fr epi epo api apo fpi fpo sy 20 256 304 0 8 0 0 0 352 0 621 4540 56 896 0 0 0 0 0 4636 0 1005 4432 12 644 0 0 0 0 0 4384 0 906 680 180 136 0 8 0 0 0 1056 0 502 2328 60 468 0 0 0 0 0 2296 0 592 1300 380 272 0 0 0 0 0 1704 0 1095 2816 72 560 0 0 0 0 0 2940 0 709 4084 40 416 0 0 0 0 0 4220 0 894 2764 4 276 0 0 0 0 0 2700 0 566 1824 96 328 0 0 0 0 0 2072 0 556 3408 80 392 0 20 0 0 0 3496 0 857 2804 92 552 0 4 0 0 0 2924 0 741 1344 16 272 0 0 0 0 0 1376 0 289 3284 52 520 0 12 0 0 0 3260 0 743 4832 200 812 0 0 0 0 0 5292 0 1276 11052 56 2200 0 0 0 0 0 8676 0 2326 5256 328 1020 0 8 0 0 0 4404 0 1725 re maj mf fr epi epo api apo fpi fpo sy 404 340 72 0 64 0 0 0 536 0 1135 Great! Activity from the tar command such as "fpi"s can be clearly seen.