I got a win r2 vm with 4096 gb RAM. Memory usage alarms are being triggered on the vm.
Active memory shows as 3.96GB
However in the guest the commit charge is only 3.3gb.
How is this possible? from what I understand if the vm was actively using 4gb or ram then commit charge would have to be at least 4gb
Accepted Solutions
Robert Moore wrote:
Wow, great page, that the best explanation i've seen on the web. I've bookmarked that.
Thanks! (I wrote it.) 
Now i guess I can answer my own question, the reason active memory is so high is that my file cache (not represented in commit charge) must be very active?
Yes, Windows 2008 is quite aggressive to use any spare memory for caching purposes. Since it does not know it is virtualized this is a good behavior to actually make use of all memory that someone has bought to it.
Robert Moore wrote:
I got a win r2 vm with 4096 gb RAM. Memory usage alarms are being triggered on the vm.
What exactly is the Windows OS version? Is it a Windows 2003 R2 or 2008 R2?
If it is 2003 R2, is it 32 bits? That would explain why the guest does not reach more than 3.3 GB.
Wow, great page, that the best explanation i've seen on the web. I've bookmarked that
Now i guess I can answer my own question, the reason active memory is so high is that my file cache (not represented in commit charge) must be very active?
One other question - what is the difference between the commit value (3159) and the 3.69gb in the green bar ?
Robert Moore wrote:
Wow, great page, that the best explanation i've seen on the web. I've bookmarked that.
Thanks! (I wrote it.)
Now i guess I can answer my own question, the reason active memory is so high is that my file cache (not represented in commit charge) must be very active?
Yes, Windows 2008 is quite aggressive to use any spare memory for caching purposes. Since it does not know it is virtualized this is a good behavior to actually make use of all memory that someone has bought to it.