Some way for multiple Tor processes to share directory information
From the '(D)DOS over Tor' thread on tor-talk...
Hi yes we agree, we think that this is the best solution, currently. We'll upgrade our hardware asap, adjust the scripts to have a dedicated Tor daemon for each virtual host and hopefully move on.
What you'd most likely want in that case is a single master tor daemon to manage the network info such as obtaining the consensus and for any other sort of meta stuff you wish it to manage, and a bunch of slaves that save bandwidth/cpu/ram/disk by looking to the master for that info.