> Anti-compaction and streaming is done to move data from nodes that > have it (that are in the replica set). This implies CPU and I/O and > networking load on the source node, so it does have an impact. See > http://wiki.apache.org/cassandra/Streaming among others. > > (Here's where I'm not sure, someone please confirm/deny) In 0.6, I > believe this required diskspace on the originating node. In 0.7, I > *think* the need for disk space on the source node is removed. >
That is correct. In 0.6, an anticompaction was performed and a temporary SSTable was written out to disk, then streamed to the recipient. The way this is now done in 0.7 requires no extra disk space on the source node. - Tyler
