Filesystem buffer size

[cscott at speakeasy.net]

I have a server thats sole purpose for existence is serving a fixed group of files from a dedicated filesystem. There is a directory tree with about 50K files that is requested in a random order. I have been trying find the correct sysctl variable to dedicate more RAM to the filesystem buffer to reduce the latency in the server caused by the FS reads. Is there such a variable? What is the variable I should be working with? vfs.maxbufspace is read-only.

TIA
Casey