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MICDROP
Enthusiast
Enthusiast

Understanding the "Memory" in vSphere

Hi, All.

I have a really hard time understanding the memory utilization seen in vCenter and Guest OS.

VM tab in ESXi.png

The above picture is taken from the VM tab in the ESXi Host.

The Host Mem values of the VMs with the same amount of memory are all different.

Is this just because of the units MB, MiB, GB, GiB?

vCenter Memory & Guest OS Memory.png

The picture above is taken from VM in vCenter and the blue box is the Task Manager taken from the actual guest OS.

Although vCenter indicate it uses 1.16GB out of 4GB, 84% of the actual guest OS is in use.

The 84% usage shown by the Guest OS means that it uses about 5GB.

Because the usage gap between vCenter and Guest OS is so severe, I have a lot of difficulty explaining this to the customer.

I would really appreciate it if you could give me an explanation or a link to these two problems.

Everyone, please be careful of the covid-19. Thank you for advice.

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scott28tt
VMware Employee
VMware Employee

Chapters 5 and 6 are an essential read in understanding how memory is handled: https://docs.vmware.com/en/VMware-vSphere/6.7/vsphere-esxi-vcenter-server-67-resource-management-gui...


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Blaze4up
Enthusiast
Enthusiast

Hi Micdrop,

Memory is indicated in three types, granted, consumed and active memory.

So, your vm has been grandted with 4 GB of memory. The 1.16 Gb is active memory.

But this is only for that moment of time, if you hit the refresh button, the numbers could be different.

maybe this will help VMware Knowledge Base

Consumed Host Memory vs Active Guest Memory

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