memory utilization with ArcGIS Server 10.1 - request for recommendations

[ArtUllman]

I am trying to understand how memory is allocated with 10.1 running in a Windows 2008 environment.  I installed 10.1 on a Virtual Machine with 4GB of RAM.  We were using 90% of available memory and I started having issues with services crashing.  I bumped memory to 16GB of RAM and have not had any issues with services crashing, but I am at 90% memory utilization again.  I am using default heap settings.  We are currently running a single instance/machine (no clusters).  We have not worked out our load balancing configure yet.  I have the following questions:

1. Will ArcGIS Server try to allocate X% of the memory on the system?  If so, what percent is normal?
2. How much memory should I expect to consume for each service/process?  I am running low isolation with minimum instance of 1 and max of 4.
3. What are the recommendations for setting the HEAP allocations?
4. Alot of our services use Query Layers.  Does that change anything in regard to tuning or memory allocation?

I am planning on doing to load testing, but would like a better understanding of memory utilization for 10.1.  We are trying to plan and design a stack for our production environment and are trying to understand memory utilization with the new ArcGIS Server.

Thanks,

Art Ullman

[BillEveringham]

Try setting your minimum instance to "0" it seemed to work for me.

[JarrodChristensen]

Art

Found this on the Resources Website [HTML]http://resources.arcgis.com/en/help/system-requirements/10.1/index.html#//015100000072000000 [/HTML]

Hardware requirements
For a development environment, the minimum RAM requirement for ArcGIS Server is 4 GB. This requirement is based on a typical development server with the following environment:
�?�Two cached map services
�?�One dynamic map service
�?�One locator service
�?�One geoprocessing service
�?�Geometry service
�?�PrintingTools service
�?�SQL Server Express
�?�IIS with Web Adaptor
For a production environment, hardware minimum requirements are not listed because user and business needs of ArcGIS Server may vary. These requirements must be considered in determining hardware needs to meet user performance expectations and scalability. Please refer to the Infrastructure Performance Considerations and System Design Strategies wiki for assistance in designing a Server infrastructure that would meet your business requirements.

Hope this info helps

[ArtUllman]

Thanks.  I was hoping to get some sort of idea as to how memory is allocated in 10.1. In 10.0 on IIS, I was able to monitor memory utilization as additional SOC processes spawned. In 10.1, it looks like it allocating about 80% of 16GB of the memory for only about 12 concurrent SOCs.  I am wondering if it is pre-allocating memory based on availability in the system. If this is true, then I need some sort of metric or perfmon stat I could use to determine memory requirements.  I don't want to wait until I start paging to determine it is time to add memory.

[ArtUllman]

It turned out that the memory issues we were running into were related to the Virtual Machine (VMWare) configuraton.  The VM really only had 4GB of phyisical memory, even though the OS was showing 24GB. VMWare uses something called a balloon driver to trick the OS into thinking it has more memory than it really has if you do not allocate the physical memory to the VM.  The balloon driver grabs all of the 'fake memory' so it looks like you have very high memory utilization on the server.  In reality, the balloon driver has grabbed all of the fake memory you see in task manager. 

Once the VMWare configuration was corrected, all of our memory problems were solved.  Memory utilization is now on par with our expectations - less than 8GB for 35 services.

[nicogis]

see also: http://wiki.gis.com/wiki/index.php/Server_Software_Performance
for test: http://www.arcgis.com/home/item.html?id=e8bac3559fd64352b799b6adf5721d81