Guest Memory Help Please...

[StressedOut]

Can someone explain in simple terms what these figures, taken from the "Virtual Machines" tab of my vSphere client mean...

(The 1=, 2=...  refer to my virtual machines)

Host Mem - MB 1=4149, 2=11887, 3=2138, 4=3111, 5=1981, 6=4121

Guest Mem - % 1=13%, 2=7%, 3=3%, 4=13%, 5=7%, 8=12%

Memory Size - MB 1=4096, 2=12288, 3=3072, 4=3072, 5=2048, 6=4096

Is my current understanding correct - Take VM1, I have configured 4096MB of RAM in the guest (Memory Size), ESXi has taken 4149MB (Host Mem) from my RAM pool and i am only using 13% of this ram (532k) (Guest Mem)????

Are the Host Mem figures higher than the Memory Size figures because of ESXi overheads??

Do any of these figures indicate that i have massively overallocated RAM from my pool??

The operating systems are 1=2003SBS, 2=2008r2, 3=XP, 4=XP, 5=XP, 6=vSphere virtual application

Thanks

Dave

[jrmunday]

Hi Dave,

Host Mem - MB

Host memory utilization statistics, in MB. This is also known as consumed host memory. This is between 0 and the configured resource limit. Valid while the virtual machine is running. This includes the overhead memory of the VM.

Guest Mem - %

Guest memory utilization statistics, in MB. This is also known as active guest memory. The number can be between 0 and the configured memory size of the virtual machine. Valid while the virtual machine is running.

This is the guest VM's active memory divided by the allocated memory - in your example, I suspect that VM1 has an active memory value of ~ 532.48 MB (ie. 532.48 / 4096 = 13%)

Memory Size - MBb

This is your memory allocation - ie. VM1 had 4GB of allocated RAM (4096MB)

Are the Host Mem figures higher than the Memory Size figures because of ESXi overheads??

Yes, this includes the overhead memory of the VM.

Do any of these figures indicate that i have massively overallocated RAM from my pool??

It doesn't look like (apart from VM2 which has 12GB allocated, and only 3% active) - but without understanding the role / workload of this server It would be hard to tell.

Cheers,

Jon

[StressedOut]

Thanks for that,

Vm2 runs 2008r2 and is our remote desktop server, it serves 15 clients with various apps and also Internet access etc plus print services for the RDP users.

Vm1 runs 2003sbs and is our DNS, DC, AD, SQL database and file server plus print services for non RDP users.

The RDP server never seems to use much active memory etc, I allowed 1gb per user on setting it up then later tweaked that down a bit, it must be extremely efficient at memory conservation?

[jrmunday]

Use esxtop and the built in performance charts to understand the resource utilisation - you'll soon get a feel for it and know if there are issues.

http://www.yellow-bricks.com/esxtop/

Vm1 runs 2003sbs and is our DNS, DC, AD, SQL database and file server plus print services for non RDP users.

You probably want to make sure that VM1 is up before the others.

The RDP server never seems to use much active memory etc, I allowed 1gb per user on setting it up then later tweaked that down a bit, it must be extremely efficient at memory conservation?

Yes, in my experience memory management in vSphere 5.0 is extremely efficient.

See this whitepaper;

http://www.vmware.com/files/pdf/mem_mgmt_perf_vsphere5.pdf

[StressedOut]

Thanks for that,

From the whitepaper link...

Quote "Set an appropriate virtual machine memory size. The virtual machine memory size should be slightly larger than the average guest memory usage."

Does that imply that my VM2 settings could be reduced to say 1gb as the average is only 532mb??

Not that i would go this low of course but just trying to get a hold of the system.

[iw123]

Yes, you could likely reduce the memory allocation to be closer to what the guest is actually using - just remember to account for any spikes such as backup windows etc.