How to Set Cassandra Volumes on AWS

The best way to think of a cassandra database is not as a set of databases on different nodes, but as one single database. Adding the column to the first node adds it to all other nodes. The actual number of times your data is written is determined by your replication strategy and replication factor, but each copy of the data will be the same.

Thus, if you tell the first node about a new column, the second node will automatically understand it and be able to access that data. If you tell the second node about different data in the same column, it will either overwrite the old data or add new data, depending on whether the row you're writing into already has data in it.

If you're adding a new column to the second node, then all the data in that column and the data in the first column will simultaneously exist and can be queried through either/any node.

I had the same problem and, based on smurty's answer, I managed to do it by adding a new property 'storage.cassandra.keyspace' for each declared graph in rexster-cassandra-es.xml configuration file.

Since I'm using version 0.5.4 with default Cassandra+ElasticSearch configuration, this is the documentation that helped me.

Now I have one graph using the keyspace 'titan' (default value), and another one with the exact same configuration except for that property, which has value 'global'. In folder '$TITAN_HOME/db/cassandra/data' there are two folders, 'titan' and 'global', one for each graph's data.