Somewhere towards the bottom of my todo list is a script that will plot a graph based on the hourly data logged by the toaster to syslog (x NFS ops, y CIFS ops). Not particularly informative, but an indication of when the high and low usage periods are.
I have such a beast, but it's a ghastly hack (the ops are a variable number of words from the beginning of the line, but a fixed number from the end - so I used rev), and the output is in gnuplot commands, so I have to run it through gnuplot to create postscript, and then manually through xv if I want a .gif to pu on a web page... it's a lot of work.
Bruce