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I am using vFoglight and get this error, "[Critical] Virtual machine X has moved virtual machine memory from physical pages to the VMware swap file within ESX. This may adversely affect performance on this VM. The following URL can be used to obtain alarm details. "

So I am unsure what this is saying. Is this saying:

1) That the ESX host is moved the swap (page file) from Windows server X outside the virtual disk for that Windows host to the ESX swap that was setup when ESX was installed?

2) That the hypervisor swapped the whole VM out of memory (using physical RAM) to the whole VM using the ESX swap for it's memory (making it much slower)?


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up vote 0 down vote accepted

It sounds like you have maxed out the physical RAM in the host, and now VMware is starting to pagefile. It's not necessarily all of the RAM, but at least some of it. You need to take a look at your host and see how much RAM is in use - you should have an alert if you are really maxed out. The real problem is that VMware is oblivious to the memory usage in the guest. If it happens to pagefile lesser-used RAM, you might not see a significant performance hit. However, if it happens to page the most active RAM, your performance could slow to a crawl. There's no control over this - is purely by chance what it decides to pagefile.

In my experience, VMware tends to run out of RAM before running out of CPU, so generally increasing the physical RAM in the host will resolve the issue. You do need to be careful about capacity planning down the road though!

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Yeah that was our issue. All sorts of new hardware now and the issue has gone away. – Chadddada Feb 18 '11 at 19:03

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