i am running esxi 5.5 with only one virtual mashine. At the beginning host memory consumed was 550 MB but after 3 days it increased to almost 1200 MB.

My guest is using the same amount all the time. What is the reason ?

esxi vSphere

  • How much RAM does your guest actually have allocated to it? Mar 9, 2014 at 8:00

1 Answer 1


Can you clarify what you mean by "My guest is using the same amount all the time"?

I suspect the problem is that you're misunderstanding this part:

enter image description here

That metric is not a measure of how much RAM the guest is using; it's a measure of how much of the RAM that's been allocated to the VM has been used recently (the number that's at 46 MB in the image). It's a measure of the activity within the VM's RAM, which is useful when ESXi is deciding how to allocate RAM when there's resource contention.

The reason that the Host Memory number is going up is that a modern (Windows or Linux) will utilize any physical RAM that's available to it as a filesystem cache - as the system's running, it'll gradually use all of the physical RAM that you've allocated to it (1.5 GB), and it will keep it used unless there's memory contention among VMs (then the balloon can take RAM back).

This is normal and to be expected - the important thing to remember is that the active memory metric is a measure of recent use of the RAM, not an amount of consumption.

  • You are right i misunderstood the "guest part". Thanks for explanation.There is over 500 computers behind "webfilter" vmaschine and i had been worried it was going to crash. Now i am going to have smooth sunday :)
    – Kriss
    Mar 9, 2014 at 8:16
  • 2
    Memory can only be used or wasted. You can't save it for later. Mar 9, 2014 at 8:45

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