Warren Young wrote:
On Nov 18, 2015, at 1:20 PM, Kwan Lowe kwan.lowe@gmail.com wrote:
Because of caching, from VMWare's perspective, all Linux memory is being "used”.
Nope. VMware’s memory ballooning feature purposely keeps some of the guest’s RAM locked away from the kernel. This is where RAM comes from when another guest needs more physical RAM than it currently has access to:
https://blogs.vmware.com/virtualreality/2008/10/memory-overcomm.html
There are downsides.
<snip>
Another, of course, is that oversubscription risks running out of RAM, if all of the guests decide to try and use all the RAM the host told them it gave. All of the guests end up being forced to deflate their balloons until there is no more balloon memory left.
<snip> Note that in '09, VMWare was advising us (where I was working at the time) to not go over 2 or 2.5 times real memory....
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