Memory Overhead Formula

[ENeumann]

Does anyone know where I can find the formula to calculate the memory overhead a VM has? I know there was one for an older version of VMWare but I've searched the documentation adn I can't seem to find any reference to a formula anymore... I have this handy dandy chart but a lot of my VMs memory sizes aren' on that chart...

Table 9 2. Overhead Memory on Virtual Machines

Virtual CPUs	Memory (MB)	Overhead for 32-bit virtual machine (MB)	Overhead for 64-bit virtual machine (MB)
1	256	79	174
1	512	79	176
1	1024	84	180
1	2048	91	188
1	4096	107	204
1	8192	139	236
1	16384	203	300
2	256	97	288
2	512	101	292
2	1024	101	300
2	2048	125	316
2	4096	157	349
2	8192	221	413
2	16384	349	541
4	256	129	511
4	512	133	515
4	1024	141	523
4	2048	157	540
4	4096	189	572
4	8192	222	605
4	16384	350	734

Your help is much appreciated.

[azn2kew]

You can use this tool to plugin your virtual machine memory requirements and it will generate the results for you at

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Regards,

Stefan Nguyen

VMware vExpert 2009

iGeek Systems Inc.

VMware, Citrix, Microsoft Consultant

[ENeumann]

Yeah, i've seen this page before. That doesn't tell me how much memory to allocate to the VMs for VM Kernel. That's the bit I need to find out so I know how large to make the memory for my VMs. I'm looing for some sort of formula to replace the chart I have above. See, it doesnt have certain memory levels on there and I want to be as exact as possible.

[azn2kew]

Have you read this thread, it has several tools and a formula you can check out http://communities.vmware.com/thread/102973

If you found this information useful, please consider awarding points for "Correct" or "Helpful". Thanks!!!

Regards,

Stefan Nguyen

VMware vExpert 2009

iGeek Systems Inc.

VMware, Citrix, Microsoft Consultant

[ENeumann]

I've seen that thread too... It doesn't seem to be what I'm looking for either... I'm trying to find how best to plan for VMs in my enironment. I know how much memory I want to give each Vm, I just nee to plan for the overhead that VMWare tacks on to whatever I have. This chart above is wonderful adn all but I've got servers with 10GB of memory and thats not on the chart... How did VMWare come up with the numbers in this chart? I assumed it was from some formula they devised. Thats what I'm looking for

[azn2kew]

Its hard to come by that's all I can get why don't you try 150MB for the overhead it seems to fit the bill.

If you found this information useful, please consider awarding points for "Correct" or "Helpful". Thanks!!!

Regards,

Stefan Nguyen

VMware vExpert 2009

iGeek Systems Inc.

VMware, Citrix, Microsoft Consultant

[ENeumann]

I'm not trying to figure out how much memory to give a VM, I already know that. I'm trying to figure out how much extra memory my VM is going to use thanks to the overhead VMWare has. This is really for planning purposes. I want to know the impact of bringing up a new VM in my environment. That way, I know when to purchase more resources.

[azn2kew]

Isn't it the chart said the over head for 32bit machine for 8GB RAM is 132MB? If you have 10GB RAM machine wouldn't it be good at 150MB for the overhead? If not, good luck finding the right info.

If you found this information useful, please consider awarding points for "Correct" or "Helpful". Thanks!!!

Regards,

Stefan Nguyen

VMware vExpert 2009

iGeek Systems Inc.

VMware, Citrix, Microsoft Consultant

[ENeumann]

No, a 64bit machine with 10GB of ram should use between 400 and 600MB of overhead. Thats the problem. I want an exact amount of overhead to plan for whatever level of RAM I have. It seems hopeless though. Maybe I'll just round up to the next level on the chart and plan for the absolute worst 😕