Hey all - My company is working on introducing a configuration service system to provide cofig data to several of our applications, to be backed by Cassandra. We're already using Cassandra for other services, and at the moment our pending design just puts all the new tables (9 of them, I believe) in one of our pre-existing keyspaces.
I've got a few questions about keyspaces that I'm hoping for input on. Some Google hunting didn't turn up obvious answers, at least not for recent versions of Cassandra. 1) What trade offs are being made by using a new keyspace versus re-purposing an existing one (that is in active use by another application)? Organization is the obvious answer, I'm looking for any technical reasons. 2) Is there any per-keyspace overhead incurred by the cluster? 3) Does it impact on-disk layout at all for tables to be in a different keyspace from others? Is any sort of file fragmentation potentially introduced just by doing this in a new keyspace as opposed to an exiting one? 4) Does it add any metadata overhead to the system keyspace? 5) Why might we *not* want to make a separate keyspace for this? 6) Does anyone have experience with creating additional keyspaces to the point that Cassandra can no longer handle it? Note that we're *not* planning to do this, I'm just curious. Cheers, Martin
