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iopattern_example.txt revision 1.1.1.1 
      1 The following is a demonstration of the iopattern program,
      2 
      3 
      4 Here we run iopattern for a few seconds then hit Ctrl-C. There is a "dd"
      5 command running on this system to intentionally create heavy sequential
      6 disk activity,
      7 
      8    # iopattern
      9    %RAN %SEQ  COUNT    MIN    MAX    AVG     KR     KW
     10       1   99    465   4096  57344  52992  23916    148
     11       0  100    556  57344  57344  57344  31136      0
     12       0  100    634  57344  57344  57344  35504      0
     13       6   94    554    512  57344  54034  29184     49
     14       0  100    489  57344  57344  57344  27384      0
     15      21   79    568   4096  57344  46188  25576     44
     16       4   96    431   4096  57344  56118  23620      0
     17    ^C
     18 
     19 In the above output we can see that the disk activity is mostly sequential.
     20 The disks are also pulling around 30 Mb during each sample, with a large
     21 average event size.
     22 
     23 
     24 
     25 The following demonstrates iopattern while running a "find" command to
     26 cause random disk activity,
     27 
     28    # iopattern
     29    %RAN %SEQ  COUNT    MIN    MAX    AVG     KR     KW
     30      86   14    400   1024   8192   1543    603      0
     31      81   19    455   1024   8192   1606    714      0
     32      89   11    469    512   8192   1854    550    299
     33      83   17    463   1024   8192   1782    806      0
     34      87   13    394   1024   8192   1551    597      0
     35      85   15    348    512  57344   2835    808    155
     36      91    9    513    512  47616   2812    570    839
     37      76   24    317    512  35840   3755    562    600
     38    ^C
     39 
     40 In the above output, we can see from the percentages that the disk events
     41 were mostly random. We can also see that the average event size is small - 
     42 which makes sense if we are reading through many directory files.
     43 
     44 
     45 
     46 iopattern has options. Here we print timestamps "-v" and measure every 10
     47 seconds,
     48 
     49    # iopattern -v 10
     50    TIME                 %RAN %SEQ  COUNT    MIN    MAX    AVG     KR     KW
     51    2005 Jul 25 20:40:55   97    3     33    512   8192   1163      8     29
     52    2005 Jul 25 20:41:05    0    0      0      0      0      0      0      0
     53    2005 Jul 25 20:41:15   84   16      6    512  11776   5973     22     13
     54    2005 Jul 25 20:41:25  100    0     26    512   8192   1496      8     30
     55    2005 Jul 25 20:41:35    0    0      0      0      0      0      0      0
     56    ^C
     57 
     58