HBase. With the caveats that it&#x27;s piggy backing off the success of Zookeeper, and the tests were not run by Kyle himself:<p><a href="http:&#x2F;&#x2F;old.eng.yammer.com&#x2F;call-me-maybe-hbase&#x2F;" rel="nofollow">http:&#x2F;&#x2F;old.eng.yammer.com&#x2F;call-me-maybe-hbase&#x2F;</a><p><a href="http:&#x2F;&#x2F;old.eng.yammer.com&#x2F;call-me-maybe-hbase-addendum&#x2F;" rel="nofollow">http:&#x2F;&#x2F;old.eng.yammer.com&#x2F;call-me-maybe-hbase-addendum&#x2F;</a>