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Robert Advancedidea

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Windows Server 2008 R2 consuming all available RAM for CACHE

I am running a windows server 2008 R2 standard as a host for 6 virtual machines. The server has 2 x quad core XEONS and 32GB of Ram.

After I restart the host, I can boot all the virtual machines boot and consume the expected amount of RAM and for a few hours cache RAM remains low when viewed from TASK Manager. If I log in 6 to 10 hours after the host is restarted and all VM's are running, the HOST has consumed all remaining RAM (as much as 12GB) into CACHE and leaving ZERO FREE memory.

At first I thought this might be a Backup Program I was running, so I uninstalled it, and other than the base services for the HOST, I have no other applications running on the HOST. I have no idea why the server is consuming ram and I'm not sure if this is or can be affecting the performance of the VM's. Any thoughts on how to manage the CACHE memory or even how to clear it would be appreciated.
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Robert Advancedidea

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Update, I installed Microsoft Security Essentials a ran a virus scan to see if it was a bug, the scan came back clean. Attached is an image of the results of RAMMAP: the memory being consumed is in MAPPED FILE

User generated image
Cache memory is not necessarily/technically consumed memory.  It can be allocated to processes requesting memory.  If you want to see how much memory is actually available to processes, start the resource monitor (Start->Programs->Accessories->System Tools->Resource Monitor or also available as a button on the Performance tab of the Task Manager) and select the Memory tab.  At the bottom of the Memory Tab, you'll see a graph of total memory.  

Hardware Reserved - video memory, BIOS, HW resources, etc
In Use - claimed by OS or processes
Modified - memory that has data that would have to be flushed to disk before released for swapping
Standby - memory released but still linked to processes, can be reallocated to processes
Free - not yet allocated memory


The "Available" entry at the bottom of the graph is essentially what the OS can provide to requesting processes.

Here's an article that provides a lot more details
Update: I have removed 12 GB of RAM since that was the lat thing I did before I noticed this problem. I am now running 24GB ram
Thanks gt2847c:
Attached is a copy of the resource monitor stats: Based on what you are saying, the "10891 MB Available" which includes 777MB of FREE ram is actually available for other processes and services, so then I should not be concerned about performance issues like Network connections or disk writes. I will read the article.

 

Thank you.
ResourceMonitor.jpg
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gt2847c
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