NFS server usage

[Michael Conlen]

This might be more of an NFS question in general, but I'm not sure, so 
I thought I'd try here.

I've got a FreeBSD NFS server behind two FreeBSD webservers (all 4.9) 
who load all their pages from the NFS filesystem and I'm seeing less 
traffic from the NFS server than I expected. The webservers are serving 
20Mbit/sec of traffic while the NFS server is only sending 1Mbit/sec of 
traffic. I know the bulk of the traffic generated is static 
pages/images off the filesystem.

Does FreeBSD's NFS implementation allow for caching of documents on the 
client side, either its self or through the VM system's inactive pages?

The reason I'm asking is that I'm trying to size an NFS server using a 
few of many similar sites that I hope to cluster. The performance so 
far has been great, but I'm worried that there's something I'm missing 
here that will cause the performance/usage to change in a very 
nonlinear way. Any thoughts on the subject are appreciated.

--
Michael Conlen