Simon Willison’s Weblog

hash_ring 1.2. A Python library for consistent hashing with memcached, using MD5 and the same algorithm as libketama. Exposes an interface that is identical to regular memcache making this a drop-in replacement.

# 5th May 2009, 1:45 pm / amir-salihefendic, caching, consistenthashing, django, hashring, libketama, md5, memcached, python

Project Voldemort. Yet Another “big, distributed, persistent, fault-tolerant hash table”—this time from LinkedIn, released under the Apache 2.0 license. The approach to consistency is interesting—instead of using distributed transactions, they use versioning and “resolve inconsistencies at read time”. It also uses consistent hashing (as seen in libketama) to select servers. The design document has lots more information.

# 17th January 2009, 7:45 pm / consistency, hashtable, keyvaluepairs, libketama, linkedin, open-source, scaling, versioning, voldemort