> For most systems the single master system and its potential for catastrophic downtime if failover goes badly (which it _always_ does eventually; if you claim

> For most systems the single master system and its potential for catastrophic downtime if failover goes badly (which it _always_ does eventually; if you claim otherwise you are a novice or selling snake oil) is the worse choice. I don't know what you're talking about. If implemented correctly, a hierarchical system is extremely unlikely to fail. I mean, if your network is split into 3 partitions, the master will be unavailable, but in that situation you're going to have worse problems than availability, because your web-servers are unlikely to be even reachable from outsite the datacenter. > I call BS. An O(1) routing p2p system like Cassandra has no inherent speed disadvantage over a heirarchical system. Nope. If you have a master that stores the dictionary, then all lookups are also O(1). Even better, you can randomly distribute keys across the nodes and are not bound by the hashing algorithm. I don't know about the performance between HBase and Cassandra; I'm strictly talking about theoretical performance.