9 Replies Latest reply on Jun 2, 2007 8:08 PM by boogieshafer

    Poor disk perfomance

    Maxtm Novice

      Hi all,


      i have a strange performance problem with windows 2000 server or windows 2003 server.

      I have a Dell PE 2650, 2 GB Ram 2* CPU 2,4.

      i install windows 2003 server as host system and i test disk performance: 60 MB /sec with 1-2% cpu load.


      I try to install on same server my linux mandriva 2006, vmware server 1.02 and now i try to set up a virtual-machine with same windows 2003 server now as guest os.

      Same test i do before now give me 10-20 MB /sec with high cpu load (30% to 80%).


      I try also to install a guest linux machine and now my disk performance test give me 60 MB/sec with no cpu load.


      I try after to install a guest windows 2000 professional, test give me 50-60 MB /sec with 10-15% cpu load.


      Same test with windows 2000 server give me 10-20 MB /sec with high cpu load (30% to 80%).


      So, it seem that windows server family (2000 2003) as guest  have some problem with disk performance.


      Any ideas ?

        • 1. Re: Poor disk perfomance
          nick.couchman Champion

          Any differences in how you have the virtual machines set up?  (Amount of RAM, vCPUs, etc.)

          • 2. Re: Poor disk perfomance
            Maxtm Novice

            no, same configration, same virtual disk

            • 3. Re: Poor disk perfomance
              Maxtm Novice



              windows 2000 server now work well, after some microsoft update,

              windows 2003 server still bad performance, i suppose that i have bed performance because windows is using full CPU (100%) on disk i/o.

              • 4. Re: Poor disk perfomance
                Maxtm Novice

                Anyone can help me ?

                i still have a bad windows 2003 server disk performance \!!!

                • 5. Re: Poor disk perfomance
                  netpower Lurker


                  What kind of disks are you using ?

                  2 GB of memory is not to small ? How much memory the host is using, and how much are you allocating to the VM ?

                  Did you consider the possiblity of memory swapping on the disk ?

                  Do you use the same physical disk for the host and the VM ?



                  • 6. Re: Poor disk perfomance
                    IdeCable Novice



                    I just had a "poor disk performance" issue over my vm this morning.


                    Check out my post:




                    The fix worked for me

                    • 7. Re: Poor disk perfomance
                      Maxtm Novice

                      hi, tanx for reply.   


                      i had tested virtual SCSI disk (LSI and BUSLOGIC) and ide disk but all them have the same problem.  

                      I also had tried to add following option to my vm: 

                      MemTrimRate = "0" 

                      mainMem.useNamedFile = "FALSE" 

                      with no result.   

                      After upgrading vmware server from 1.02 to 1.03 preformance are better but not enough.  I do other tests, and i see that my performance problem is in high cpu utilization on disk i/o.  when i do test on same machine but with windows 2003 server native (host system) i give about 100 MB / sec with a 3% of CPU utilizzation, same system with windows 2003 as guest and linux mandriva + vmware server 1.03 as host system give me a 80 MB /sec with 100% cpu utilizzation.    

                      When i had test windows as host system i installed 2 GB of ram, while in other test i installed 4 GB of ram, givin guest the same 2 GB ram, leaving linux host system 2 GB of ram as difference.   

                      Linux host and windows guest are on different disks, i also try giving to the vm an intere phisical disk, but still the problem.   

                      It seems to me that windows 2003 server is not using dma for disk or similar.   



                      Any help ?

                      • 8. Re: Poor disk perfomance
                        Maxtm Novice

                        anyone can help me ?

                        • 9. Re: Poor disk perfomance
                          boogieshafer Expert

                          i would try a few things and compare your results


                          1. try using different NTFS allocation sizes in your virtual disks (e.g. explicitly formatting with 8K, 16K, 32K, etc, insted of the default 4K).


                          e.g. "format e: /fs:ntfs /a:8192 /y"



                          2. try using the buslogic adapter type instead of lsilogic (or viceversa)


                          running whatever disk io benchmarking tool you have been using against these different configuratons will give you an idea what setup will work best on your hardware.




                          you may also want to try different underlying HOST filesystems and/or allocation sizes. generally i format my HOST NTFS volumes which contain the vmdk files at 64K. on linux there is a wide range of different filesystems and YMMV with each