>> I note that Hsieh's SuperFastHash is already implemented in >> GlusterFS and is used for other purposes. It's about 3x as fast as the >> DM hash, and has better collision resistance as well. MurmurHash >> (http://murmurhash.googlepages.com/) is even faster and more collision >> resistant. For future releases, I suggest dropping the DM hash and >> switching to one of these others. >> We will investigate murmurhash and see if it suits the role better. What we look for in the hashing algorithm is better hash distribution specifically for filenames (ascii strings 1-255 characters long). Better distribution of user data in general is not of much help for DHT's needs. DM hash does a very good job in distributing hashes for ascii strings 1-256 bytes long (file basenames). It is also the same algorithm used in reiserfs which is very sensitive to filename hash collisions. Speed is really a micro optimization considering the small portion of time which is used for actual hash computation. Will keep you posted when we have comparison results with murmurhash. Avati
