locked
VMs or physical machines for load testing? RRS feed

  • Question

  • can someone help me understand disadvantages in using VMs over physical machines for load testing?

    thanks,

    Nesha

    Thursday, March 16, 2017 4:54 PM

Answers

  • A VM shares the resources of it host computer with other VMs. Hence the VM running the tests may have short periods where it is prevented from doing anything because of the other VMs on the host. This can lead to recorded times being longer than actual, it can also mean that CPU usage on the VM is higher.

    Recent VM management software and powerful host computers reduce the effect of these problems but it may be wise to use a VM that is the sole occupant of a host or that has sole usage of some of the hosts CPUs.

    Regards

    Adrian

    • Proposed as answer by Oscar_Wu Monday, March 20, 2017 1:29 AM
    • Marked as answer by Nesha41 Thursday, March 23, 2017 4:14 PM
    Friday, March 17, 2017 9:07 AM

All replies

  • Hi Nesha,

    There is no obvious fault when we using VMs, VMs will slow down the I/O, but test rig need not much I/O operation, so I think disadvantages are insignificant.

    Hope it helpful for you.

    Sincerely,

    Oscar


    MSDN Community Support
    Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com.

    Friday, March 17, 2017 8:34 AM
  • A VM shares the resources of it host computer with other VMs. Hence the VM running the tests may have short periods where it is prevented from doing anything because of the other VMs on the host. This can lead to recorded times being longer than actual, it can also mean that CPU usage on the VM is higher.

    Recent VM management software and powerful host computers reduce the effect of these problems but it may be wise to use a VM that is the sole occupant of a host or that has sole usage of some of the hosts CPUs.

    Regards

    Adrian

    • Proposed as answer by Oscar_Wu Monday, March 20, 2017 1:29 AM
    • Marked as answer by Nesha41 Thursday, March 23, 2017 4:14 PM
    Friday, March 17, 2017 9:07 AM
  • I agree with Adrian.

    Another approach would be to have Single core VM's that don't in total exceed the number of cores in the host computer and leave at least 1GB of memory free for the host.  The other shared resources shouldn't really be impacted.

    Cheers

    Friday, March 17, 2017 10:42 AM
  • Thank you All !!


    • Edited by Nesha41 Thursday, March 23, 2017 4:14 PM
    Thursday, March 23, 2017 4:13 PM