Useful test cases (as a goal):
* Serving a few large files.
* Serving a lot of small files.
* Improving write bandwidth in the face of a high number of read
requests (blogbench). i.e. serving reads from the swap cache
in order to give writes more of the real HDs bandwidth.
* NFS client-side data caching to reduce NFS server bandwidth.
* NFS server-side data caching to improve services to clients.
* Caching meta-data only to make find, ls, and other directory
operations much faster.
-Matt
