Swap File Question

[Len_H]

Will disabling the paging file on a Windows Server virtual machine have the same effect that it would if the server was not virtualized? That is, will the allocations from the Windows virtual machine be guaranteed to be pages of physical memory, or can the memory still be swapped to disk by the ESX server?

[AntonVZhbankov]

If you're running short on memory, ESX will try first force guest OSes in VMs to swap, just because they know better what pages to swap. After that ESX will start swapping on its own.

If you need to gurantee that ESX will never swap this particular machine you can set memory reserve for this VM.

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MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[weinstein5 · Accepted solution]

As Anton pointed out it is not the VM that decides whether its memory will be phyiscal or virtual it is up to the vmkernel in the ESX Server - if the vmkernel has plenty of available physical memory then yes removing the swap file in your VM will have the same affect and the VM will use virtual memory which the vmkernel will then place into physical memory - however if the vmkernel does not have enough memory and you have removed the vm's swap file then the vmkernel will be forced to swap to the vm's vmkernel swap file impacting the vms performance -

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