We are currently evaluating Cassandra, and using it for a small feature in production. We are only using the basic insert/get/remove from the API, with a standard column family. So far, I like a lot of what Cassandra offers, though I had some tough times with it.
* Version 0.4.2 seems very broken. Besides CASSANDRA-507 which is not fixed in the v4 version, it seems that when you do significant amount of deletes, and you try to restart the server, compaction fails pretty much most of the time in our environment. * Version 0.5 seems to be better in terms of stability from what I observed so far. Some things that would definitely be very helpful for us going forward: - Easier way to replace a node that dies. - Disk is not infinite so a way to say when you insert an entry into cassandra, how long do you want it to be available before it is deleted by Cassandra. - Better monitoring tools. It's very hard to tell how heavily loaded a node and the whole system is right now.
