Network Analyst routing service performance problem

[BradGeerdes]

Using a shapefile with a  spatial index, I've created a map service that has Network Analyst turned on. The purpose of this service is to calculate routes/mileage. The performance of the service works well (usually sub-second for even long routes) for a little while, but degrades significantly (down to multiple minutes). I've tried clearing the ArcGIS Server cache, restarting the SOC processes, and restarting the VM, but none of it seems to help. What seems to help is time - at some point the service may start working fine again. I have created a few of these and have to switch between them when one of them starts to act up. Which makes this even weirder because some will work fine (using the same shapefile) and some won't.

Specs: Windows Server 2007 VM (4-cores) with 4GB of memory, ArcGIS Server 9.3

This VM is dedicated to ESRI - the routing service specifically (although I do use ArcMap on the VM to create the service).

Any response so that I know these forums aren't worthless would be helpful.

Bill

[nicogis]

see http://blogs.esri.com/esri/arcgis/2011/02/17/arcgis-server-virtualization-dos-and-donts/
have you tried use file geodatabase?

[BradGeerdes]

see http://blogs.esri.com/esri/arcgis/2011/02/17/arcgis-server-virtualization-dos-and-donts/
have you tried use file geodatabase?

Thanks for the link. I will discuss it with our operations folks.

No, I have not tried a file geodatabase.

One thing that I did today was stop all services but one. I had about four of them running even though they were all idle. Once I did that the service I left running had the expected (sub-second) performance. From the link you sent it says that I should have 2 times the amount of memory I have (4GB) for the number of cores I currently have (4). So, could that have been part of my problem? It seems strange since the memory usage on the VM seemed fine. Also, some services would run fine while others would not.

Anyway, thanks for the response.
Bill