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jaturley
Contributor
Contributor

Host Mem - MB vs Guest mem - % on the Virtual Machines tab in VI 2.5

I am look at the status of my virtual machines on the Virtual machines tab in VI 2.5 I am confused by the Host mem - MB and Guest mem - % information. For example for a given vm the Host mem - MB is 3199 and the Guest Mem - % is 10 the memory size of the vm is 4096. What do these numbers relate to? How can the vm be using only 8% of the memory when 3199 is around 78% of 4096? Thanks for the help with this.

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lmonaco
Hot Shot
Hot Shot

Host Mem - MB is the number of megabytes (MB) of the virtual machine's memory used.

Guest Mem - % is the amount of the guest operating system's memory used.

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jaturley
Contributor
Contributor

I do not undestnad the diffrence. I would think that the virtual machine is the guest operating system.

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lmonaco
Hot Shot
Hot Shot

It is, but to the host its just a couple of files. The first number is in relationship the the host OS, and the second is in relation to the guest OS.

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jaturley
Contributor
Contributor

What do you mean by in relation to the host os vs in relation to the guest os? I guess what I am really asking is how can I tell how much memory the guest OS is actually useing from these numbers.

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admin
Immortal
Immortal

Host Memory is the amount of physical memory that has been allocated to the virtual machine. This also includes things like memory overhead, that also means that Consumed can be larger than what has been provisioned. To make it a bit more complex it should be noted that in the “Performance Tab” the “Consumed” Counter doesn’t actually include Memory Overhead!

Active Memory more or less already explains it, it is what the VMkernel believes is currently being actively used by the VM. Now it should be pointed out here that this is an estimate calculated by a form of statistical sampling.

Please refer to the following link for more information:

http://www.yellow-bricks.com/2010/12/20/vcenter-and-memory-metrics/

Please let me know if you need more information.

Anand

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