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I have suddenly ran out of my VMWare server memory, and VMware said that I can't make 2GB VM. I only have 3 VM. 3GB, 1GB, and 512MB. I turns out that ESX has less than 6GB

Usable Resources

I am sure that I have 8GB RAM, and VMWare also said so as shown here.

Physical memory

I understand that I would have 7774 usable RAM, but less than 6GB, where is my 2GB go? Why do I only have 6GB, and not 8GB or 7.7GB? and how to fix this?

Another same problem on another machine. This time with ESX 5.1 Usable resources2

And physical memory Physical memory 2

Any idea?

For anyone care to vote down this question, I think you should put a more light as why my available RAM is 6GB instead of 8GB, and answer me where does my 2GB go? I've search all google and all VMware for past 3 months, and I haven't seen any explanation.

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migrated from Apr 14 '13 at 2:32

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What error do you receive when you attempt to create the VM? – ewwhite Apr 14 '13 at 2:57
it was, obviously, no enough memory. – prd Apr 14 '13 at 15:39
any more ideas? anyone? – prd Apr 16 '13 at 13:21

You have 5906MB of total Memory capacity for VM's.

You have 4608MB of reserved Memory capacity for VM's.

You have 1298Mb of available Memory capacity for VM's.

You don't have enough available Memory capacity to run a VM with 2GB of RAM.

You'll need to adjust your memory reservations in order to make enough memory available for the new VM.

The physical memory shown on the Configuration tab and the memory capacity shown on the Resource Allocation tab are two different things.

The memory shown on the Configuration tab is the amount of physical memory in the host.

The memory shown on the Resource Allocation tab is the amount of memory that is available to virtual machines. Your problem is that you don't have enough memory available to virtual machines to run a 2GB VM.

Why the physical memory and the available VM memory are so different is beyond me.

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Actually, I am looking for why the available VM memory and physical memory is so different. I've checked another machine with 16GB, and I only have about 13GB for available VM memory. – prd Apr 14 '13 at 15:38

Look at your virtual machines. If you have specific RAM reservations, that means you're ensuring that the virtual machines have that RAM available to them. If you plan to oversubscribe or make the best use of your resources, you probably don't want the RAM reservations defined.


Check your hardware. If this is a multiple-CPU system, make sure your RAM is balanced across nodes. Then...

Update your ESXi installation.

You're currently running VMware ESXi 4.1 build 260247 from June 13, 2010!!!

The current build of ESXi 4.1 is Build 988178 from January 2013. You may be experiencing a bug.

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Yes.. I understand that, but that was not what I was asking. I was asking, why do I have 2GB less than my physical RAM? – prd Apr 14 '13 at 15:44
Because your ESXi system hasn't been updated since the 2010 build... It's probably an obscure bug. Try updating and see how that goes. – ewwhite Apr 14 '13 at 16:31
I have updated with 5.1 ESX. Same problem. This time this is from different machine. Almost all my ESX machines exhibit this behaviour. All of them 1 socket processor, the first one is Intel Xeon with second socket empty, second one is AMD single socketed with RVI enabled. – prd Apr 15 '13 at 2:40
Did you place all of your RAM on the memory banks associated with the single CPU? Using one CPU on a dual-CPU system board means that only half of the RAM slots are available. – ewwhite Apr 15 '13 at 2:57
Yes. And it has been recognized, as shown above. Normal linux installation shows full RAM available, and I've been checking them with memtest86. No defect there. Oh, as side note, I also tried to install ESX on my own machine, AMD PC. Same thing happenned. Unganged, and ganged. About 2GB is missing on 8GB machine, and a little less than 3GB on 12GB machine. – prd Apr 15 '13 at 5:46

Apart from that each VM wil consume the RAM that you have assigned plus the over head . For example if your 3GB VM have 4vCPU's it will consume 3 GB + 300 MB , it depends on how many CPU's you are assigning for the virtual machine.Depends on vCPU's + Memory Allocated.

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