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drawlinFlag for United States of America

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ESXi 5.1 Memory Ballooning

Had a VM where the memory resource allocation was set to 3286MB and the guest VM was allocated 32768GB RAM. I discovered this error when looking at memory ballooning as this VM had 20.08GB of memory ballooning. Set the memory resource allocation to unlimited and the VM continued to balloon for about a week. It stopped ballooning today at 2:45PM CST. Roughly at that time we had users who lost connectivity to an application the VM was hosting. Network connectivity did not drop and VM never locked up or BSOD'ed. With my knowledge of VMware memory ballooning, the action of VMware re-allocating memory back to this guest should not have caused any issues with the guest but I wanted to put it out there and see if I am missing something or of someone else has seen something similar to this.
Avatar of Andrew Hancock (VMware vExpert PRO / EE Fellow/British Beekeeper)
Andrew Hancock (VMware vExpert PRO / EE Fellow/British Beekeeper)
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The Balloon Driver is only inflated in VMs to recovery memory from VMs, if the host is running out of memory, of under memory pressure.

So what is your Host Performance and memory like?

A Guest VM assigned 32GB of memory is alot or memory.

What total is available in the host?

e.g. if you only have 32GB or memory in the host, and another VM requested 4GB, the balloon driver would inflate in your 32GB VM to "recover or steal " memory.

Is your VM a terminal server?
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ASKER

This particular VM was in a cluster of 3 hosts each with 192GB ram. The host the VM was running on was consuming 138GB. When the VM stopped ballooning, the memory on the host jumped to 153GB used. Although a bit high, still not dangerous (at least in my opinion)
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ASKER

And no, it's just an application server.
Very odd, the memory balloon driver would inflate in that scenario presented.
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ASKER

So you are saying its normal for it to balloon in that scenario? And when the vm stops using the balloon driver, it shouldn't negatively affect the vm right?
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Avatar of Andrew Hancock (VMware vExpert PRO / EE Fellow/British Beekeeper)
Andrew Hancock (VMware vExpert PRO / EE Fellow/British Beekeeper)
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ASKER

And I can see that happening based on how the resource allocation was set it before I took over. I just couldn't see it causing clients to drop their connection to the hosted application for a few minutes. I think something else caused them to drop their connection and then the vm memory usage dropped allowing the guest to reclaim its memory from the guest.
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compdigit44

Have you reviewed the host log files for the host and VM? What OS is the guest running?
What ESXi build are you running?