Hi, I don't know if this will be technically possible, but I just want to warn you about creating a lot of column families. When you will have a lot clients, you will have a lot of column families and, if I'm right, each column family uses memory on every node. You will run out of memory very fast, because of the non horizontal growth of the memory usage per column family (adding nodes won't resolve the problem, you will have to upgrade hardware on existing nodes, which is not Cassandra's philosophy). 

I think you should use rows or columns inside your column families as much as possible unless you have really a few clients.

Once again, I'm not a Cassandra expert. I might be wrong :-).

Alain

2011/12/21 Rafael Almeida <almeidaraf@yahoo.com>
Hello,

I am evaluating the usage of cassandra for my system. I will have several clients who won't share data with each other. My idea is to create one column family per client. When a new client comes in and adds data to the system, I'd like to create a column family dynamically. Is that reliable? Can I create a column family on a node and imediately add new data on that column family and be confident that the data added will eventually become visible to a read?

[]'s
Rafael