3 Replies Latest reply on Oct 25, 2007 11:49 AM by foster29

    MemTrimRate question

    foster29 Expert

       

      by default my memTrimRate is set to -1.   Based on some threads i have read i changed it to MemTrimRate = "0" and it has improved performance. My question however is exactley what is it doing?  I've noticed that my Total Kernel memory has increased as a result, the VM is running much better but need to understand what changing -1 to 0 is doing.

       

       

       

       

       

      thanks,

       

       

      pete

       

       

        • 1. Re: MemTrimRate question
          Peter_vm Guru

           

          No, by default MemTrimRate = "30", not "-1". Disabled memory page trimming sets this value to "0". I think "-1" has the same effect.

           

           

          VMware Server uses a memory trimming technique to return unused virtual machine memory to the host machine for other uses. Although trimming usually has little impact on performance and might be needed in low memory situations, the I/O caused by memory trimming can sometimes interfere with disk-oriented workload performance in a guest.

           

           

          To disable memory page trimming, check the Disable memory page trimming check box, and click OK.

           

           

          • 2. Re: MemTrimRate question
            172pilot Enthusiast

            Can I assume then that the trim rate values would be valid in between 0 and 30 too? 

             

            It sounds like a good thing to have happening, but performance is good too, so perhaps it'd be good to lower it instead of turning it off, if it's a rate??  Say, maybe to 10?

            • 3. Re: MemTrimRate question
              foster29 Expert

              on my system it was set to -1.  Having it set to that caused the VM to be unsable. Basically the disk I/O was so high that even simple navigation was difficult. By setting it to 0 the vm performs as expected