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