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I've never had this issue before, but when I was enabling fault tolerance, it seemed to break something and now my guests are consuming ALL of it's memory on the host.

I know with fault tolerance, you need to have the guest reserve all host memory but I have disabled fault tolerance (in the networking section, not sure if there is somewhere else) and it is still consuming all memory.

I have three Windows Server 2012 guests and they are only consuming 81MB, 204MB, and 40MB guest memory. Those three are consuming a total of 11.5GB of host memory...

Usually, they would all consume about 100MB host memory over the guest consumed memory -- and they would share all memory being they are all the same OS.

How come all of these machines are reserving all memory? Is there a setting for this somewhere in advanced settings, that enabling fault tolerance and HA enabled?

http://i.stack.imgur.com/pz6iP.png

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3 Answers 3

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I think you're misunderstanding the data here. The situation you're in has nothing to do with whether or not you have FT enabled.

The "overhead" column you're referencing really has nothing to do with how much memory the guest is consuming. Rather, that column indicates the amount of memory that the hypervisor requires to power that machine on. The hypervisor uses this "overhead" space to do its own internal bookkeeping for the VM in question.

Unless you want to get into a memory over-subscription situation (not recommended), the "Max" and "Usage" columns are where you want to direct your attention.

Additionally, I'd recommend that you spend a few quality hours going over this section of VMware's documentation on memory resources.

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@BillyRowe I'm just confused as to why all of the VMs are reserving all of their memory, which is the 'consumed' column, correct? No, the Consumed column show's what's consumed. Look on the far right of your image from RVTools for the Reservation column, which is all 0s. –  Shane Madden Oct 15 '13 at 5:42
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"when it is only using 163MB of the guest memory" <- what are you talking about? Have you not understood what we're saying? Look at the Consumed column. Your guests are using 3927+2094+4199=10220MB of RAM. –  EEAA Oct 15 '13 at 5:51
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@BillyRowe - where are you getting this 163 number? It's not on your chart. –  EEAA Oct 15 '13 at 5:55
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@BillyRowe VMs can use less than what they've been allocated through simply not using RAM (though every modern OS will use available RAM as a filesystem cache), as well as the transparent page sharing, ballooning, memory compression, and host swap memory management tools that the ESXi hypervisor uses to manage contention. A memory reservation ensures that the VM's allocation will be kept in physical RAM instead of being ballooned or compressed or swapped - that's all a reservation is. And again, where's this 163MB coming from? –  Shane Madden Oct 15 '13 at 5:58
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@ShaneMadden Okay, I understand that now! i.imgur.com/2COhG63.png –  Billy Rowe Oct 15 '13 at 5:59

So the problem is that they're using what they've been allocated?

It seems extremely unlikely that transparent page sharing is getting you that kind of savings. Are you certain you're not confusing the memory overhead statistic in vCenter with the consumed RAM?

Can you show us the "Resource Allocation" tab in vCenter for these Windows 2012 VMs using <100 MB of RAM?

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All better -- I shut down virtual machines and powered back on and now all memory is being shared. 6 GB utilized instead of close to 11. Ballooning is enabled as well so it will cut back an extra 1 or 2 GB once the virtual machines idle. I knew there was an issue with all memory being consumed and I thought this site would offer some help to the issue.

I'm guessing the automatic virtual machine startup won't balloon and share memory, until the user initiates the boot. 

Now, the 4 GB AD machine is only 286MB active and 1405 consumed host memory. That is SO much better than 200MB active and 4 GB consumed. 

Now I am happy!

Thanks for trying guys!  /closed

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You're still confusing things. Memory sharing and ballooning have nothing to do with how machines get started up. Additionally, it is obvious that a machine will consume less RAM immediately after a clean boot. This is due to the fact that it has not built up its page cache yet. Give it a few days of active use, and a guarantee that your VMs memory usage will be right where it was previously. –  EEAA Oct 15 '13 at 21:30
    
Nope. :) My DHCP server is consuming 184MB host memory, and it has been up ever since this old post. There was something wrong when I had posted this - it was consuming more memory than allocated. I guarantee it wasn't normal. I have become more familiar with vSphere, and now up to my VCP5-DCV.:) –  Billy Rowe Sep 30 at 23:57

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