I have just filed CEP-36 [1] to allow for keyspace/table storage outside of the standard storage space.
There are two desires driving this change: 1. The ability to temporarily move some keyspaces/tables to storage outside the normal directory tree to other disk so that compaction can occur in situations where there is not enough disk space for compaction and the processing to the moved data can not be suspended. 2. The ability to store infrequently used data on slower cheaper storage layers. I have a working POC implementation [2] though there are some issues still to be solved and much logging to be reduced. I look forward to productive discussions, Claude [1] https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-36%3A+A+Configurable+ChannelProxy+to+alias+external+storage+locations [2] https://github.com/Claudenw/cassandra/tree/channel_proxy_factory
