Do you prefer purpose-specific Cassandra clusters that support a single application's data set, or a single Cassandra cluster that contains column families for many applications? I realize there is no ideal answer for every situation, but what have your experiences been in this area for cluster planning?
My reason for asking is that we have one application with high data volume (multiple TB, thousands of writes/sec) that caused us to adopt Cassandra in the first place. Now we have the tools and cluster management infrastructure built up to the point where it is not a major investment to store smaller sets of data for other applications in C* also, and I am debating whether to: 1) Store everything in one large cluster (no isolation, low cost) 2) Use one cluster for the high-volume data, and one for everything else (good isolation, medium cost) 3) Give every major service its own cluster, even if they have small amounts of data (best isolation, highest cost) I suspect #2 is the way to go as far as balancing hosting costs and application performance isolation. Any pros or cons am I missing? -j