New SLOB2 Physical I/O Harness

slob ghostShort post to point out that I’ve now posted the updated PIO Test Harness for SLOB2. This can be used to run multiple SLOB tests with varying numbers of workers and values of UPDATE_PCT. In addition there is also a revised version of the AWR analyzer shell script which can be used to extract various performance values from the AWR reports outputted by SLOB2.

Having said that, SLOB2 also comes with its own data extraction tool,, so it may be that you prefer to use this depending on what data you are interested in.


7 Responses to New SLOB2 Physical I/O Harness

    • Gary Zhang says:

      I tried to run but got the following error,

      20131211-120645 Info : Calling SLOB with 022 workers
      20131211-120944 Info : Completed SLOB run for 022 workers: Tm 138
      20131211-120944 Info : SLOB Harness is 33% complete
      20131211-120944 Info : Calling SLOB with 024 workers
      20131211-121252 Info : Completed SLOB run for 024 workers: Tm 162
      20131211-121252 Ezhzng_gary@yahoo.comrror: Cannot find writable file awr.txt – exiting…
      20131211-121252 InfGary zhango : ———————————–
      20131211-121252 Info : Total submitted SLOB jobs: 148
      20131211-121252 Info : Total completed SLOB jobs: 50
      20131211-121252 Info : ———————————–
      20131211-121252 Info : FAILURE of slob-harness

      would you kindly let me know what will be the cause of it?

      • flashdba says:

        It’s impossible for me to say, you’ll have to debug it. Try running it with the -X option to get lots of debug output.

        It was expecting to find the output file awr.txt from SLOB2’s script, but on testing whether the file was present and writable it failed. So either the file wasn’t present (more likely) or it wasn’t writable.

        Since it looks like a number of SLOB jobs ran successfully I’d guess that you either ran out of space or somebody moved / deleted some files mid-run.

        • Gary Zhang says:

          Thanks, when run with -x option it worked fine but run  in background gave the error.  Anyway, from csv file, for 100% read,  Can I just plot read IOPS over read latency till it peaks, and deduct the max IOPS witk max latency?


          • flashdba says:

            Do you mean deduct? Or do you mean deduce? If the latter then yes, for that particular system. But keep in mind you are testing the whole system, including CPU and memory, not just the storage.

            • Gary Zhang says:

              Thanks! But for you last comments about ‘testing the whole system, including CPU and memory, not just the storage.’, I am a little confused. I thought SLOB2 test is artificially set smaller sga, smaller buffer cache size , to stress test the i/o?

              on the other hand, it makes sense to test different storage systems using the the same db server/same db .


              • flashdba says:

                That’s correct. But SLOB drives Oracle – and Oracle is about a lot more than just I/O. If you want to test pure I/O, use a tool like vdbench, fio or something similar. If you want to test Oracle, be aware that for every I/O call there is also a lot of CPU work such as traversing and manipulating doubly-linked lists of pointers. This means the CPUs you have will make a difference to the SLOB result…

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