How much memory will a Windows file-server be able to use effectively

In the near future we will be moving our fileserver to a newer box that will be running Windows 2008R2. I want to know how much memory Windows will be able to use for a system that is just a file-server.

In searching around I found an old document for Windows 2000 that mentions the maximum size of the file-system cache is 960MB. I suspect this limit no longer applies, but is there a new limit?

The file server will be just a standard Windows fileserver. It will have 1TB of attached storage. The large majority of the of the files accessed during the day are just typical Office documents. There are 80-100 people usually using the fileserver during a typical day. This system will only be used as a file server, it doesn't have any other roles.

  • In Windows 2008r2 is there any hard limits for the filesystem cache? What are they?
  • The server we will be re-using for this purpose currently has 4GB of memory, but it can be maxed out at 16GB. Is there any value in doing this for a Windows file-server?
  • Are there any performance counters can I look at on the existing 2003 fileserver that will tell me if adding more memory will be worthwhile.

Server 2008 can use all of the available RAM in a system to increase performance. Under 2003 that limit in size had a default value and a max size governed by SystemCacheDirtyPageThreshold. 2008 has a completely different management scheme and because of that there is an optional service (Microsoft Windows Dynamic Cache Service) you can use to manage the cache size. This service will run on 2003 but frankly is rarely a problem on 2003.

More RAM will always be helpful but the counter to look at would be hard page faults. Cache is what makes that number closer to 0.