Disk performance test with IBM ndisk64 tool

ndisk64 is  an IBM free tool to measure  IO performance of   your  disk .
You can download  and  get information  from http://www.ibm.com/developerworks/wikis/display/WikiPtype/nstress

• I have  created  7   different 10g files on all mout points in order  to  spread   IO
  dd if=/dev/zero of=/datac1/bigfile1 bs=1m count=10240
  dd if=/dev/zero of=/datac2/bigfile2 bs=1m count=10240
  dd if=/dev/zero of=/datac3/bigfile3 bs=1m count=10240
  dd if=/dev/zero of=/datac4/bigfile4 bs=1m count=10240
  dd if=/dev/zero of=/datac5/bigfile5 bs=1m count=10240
  dd if=/dev/zero of=/datac6/bigfile6 bs=1m count=10240
  dd if=/dev/zero of=/datac7/bigfile7 bs=1m count=10240
• Put the names  of the files  to   a  input file
  
  echo "/datac1/bigfile1" >filelist
  echo "/datac2/bigfile2">>filelist
  echo "/datac3/bigfile3">>filelist
  echo "/datac4/bigfile4">>filelist
  echo "/datac5/bigfile5">>filelist
  echo "/datac6/bigfile6">>filelist
  echo "/datac7/bigfile7">>filelist
• Identify  some  system values and  also  define some assumptions   about  your  system my assumptions and system   values  are
  
  Block size=8k
  Read-WriteRatio: 70:30 = read mostly(OLTP)
  Timed duration of the test in seconds =120
   Mutliple processes used to generate =3
• Start  test  for different multiple  process
     /home/sturgut/ndisk64 -F filelist  -S -r70 -b 8k -t 120  -M3
  Command: /home/sturgut/ndisk64 -F filelist -S -r70 -b 8k -t 120 -M3
          Synchronous Disk test (regular read/write)
          No. of processes = 3
          I/O type         = Sequential
          Block size       = 8192
          Read-WriteRatio: 70:30 = read mostly
          Sync type: none  = just close the file
          Number of files  = 7
          File size        = 33554432 bytes = 32768 KB = 32 MB
          Run time         = 120 seconds
          Snooze %         = 0 percent
  ----> Running test with block Size=8192 (8KB) ...
  Proc - <-----disk io----=""> | <-----throughput------> RunTime
   Num -     TOTAL   IO/sec |    MB/sec       KB/sec  Seconds
     1 -   2523632  21030.3 |    164.30    168242.34 120.00
     2 -   2442193  20351.6 |    159.00    162813.09 120.00
     3 -   2097104  17475.9 |    136.53    139807.03 120.00
  TOTALS   7062929  58857.8 |    459.83 Seq procs=  3 read= 70% bs=  8KB
• In another session Monitor  IO service times using # iostat -RDTl
• Increase  the different multiple process  and monitor  the  service time .Create a IOPS vs. IO service time chart
• Increase the number of threads to get a peak IOPS
• Be sure your queue_depth is >= number of threads
• More than queue_depth x 2 threads won’t increase thruput