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sunvmman
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memory crazy

can anybody explain me this memory thing. Here is what I understand

Virtual Machine Properties -> Hardware -> Memory

Controls how much memory the virtual machine can "see" from the host hardware.

Virtual Machine Properties -> Resources -> Memory

Controls how much memory the virtual machine and all applications can utilize from the amount allocated in Virtual Machine Properties -> Hardware -> Memory.

however, #1 is allocated from disk space - yes, if you set it to 5 gb memory it will hog 5 gb on disk . Why doesn't it just take it from the real system memory ?

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weinstein5
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swap file more specifically is et to the delta between the amount of memory available to the VM and the its reservation and is created at power on - so two examples:

  1. Available memory is 20 GB and there is no reservation the swap file will be 20 GB

  2. Available memory is 20 GB and reservation is set to 16 GB the swap file will be 4 GB

And if you set the memory of vm to 20 GB and needs more it will only get the 20 GB assigned

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mcowger
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It does - the 5gb is used as a backing store in case the host becomes over committed on memory and needs to swap the VM's memory to disk.

--Matt

--Matt VCDX #52 blog.cowger.us
sunvmman
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Hmmm starting to make sense. So If I give it 5 GB and it needs 20 GB will it ask the system for 20 ?

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mcowger
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No - the swap file will always be the same size as the assigned memory size for the VM.

--Matt

--Matt VCDX #52 blog.cowger.us
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weinstein5
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swap file more specifically is et to the delta between the amount of memory available to the VM and the its reservation and is created at power on - so two examples:

  1. Available memory is 20 GB and there is no reservation the swap file will be 20 GB

  2. Available memory is 20 GB and reservation is set to 16 GB the swap file will be 4 GB

And if you set the memory of vm to 20 GB and needs more it will only get the 20 GB assigned

If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful
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Rumple
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Also remember that in 99.95 percent of all implementations you should never need to give a VM more than 512MB-1GB of RAM. The exceptions are if you are virtualizing SQL/Exchange/Oracle,etc but unless you have a very strong understanding of virtualization as well as performance requirements and actual performance stats from physical implementations, you should not be virtualizing those type of servers except in smaller implementations, and those types of implementaitons typically only require 1-2GB of memory at most.

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