On Wed, Dec 11, 2013 at 1:35 AM, Sven Stark <sven.st...@m-square.com.au>wrote:
> thanks for replying. Could you please be a bit more specific, though. Eg > what exactly is being compacted - there is/was no data at all in the > cluster save for a few hundred kB in the system CF (see the nodetool status > output). Or - how can those few hundred kB in data generate Gb of network > traffic? > The only answer I can come up with is that the Merkle trees generated and compared by repair are of a fixed size, and don't scale with the data present in the cluster. While I'm pretty sure each node can be aware that it has little to no data to repair, it generates and compares the trees anyway. It's a bit surprising that this might be Gbs of network traffic... The system keyspace will always have some data in it, have you tried only compacting your empty keyspace instead of the whole node? If so, and it exhibits the same behavior, that seems like a bug or at least unexpected behavior to me. If you're running a modern version of Cassandra, I would file a JIRA. =Rob
