Two possibilities: 1) Hinted handoff (this will show up in the logs on the sending machine, on the receiving one it will just look like any other write)
2) You have something doing writes that you're not aware of, I guess you could track that down using wireshark to see where the write messages are coming from On Sat, Sep 10, 2011 at 3:56 PM, Jeremy Hanna <jeremy.hanna1...@gmail.com> wrote: > Oh and we're running 0.8.4 and the RF is 3. > > On Sep 10, 2011, at 3:49 PM, Jeremy Hanna wrote: > >> In addition, the mutation stage and the read stage are backed up like: >> >> Pool Name Active Pending Blocked >> ReadStage 32 773 0 >> RequestResponseStage 0 0 0 >> ReadRepairStage 0 0 0 >> MutationStage 158 525918 0 >> ReplicateOnWriteStage 0 0 0 >> GossipStage 0 0 0 >> AntiEntropyStage 0 0 0 >> MigrationStage 0 0 0 >> StreamStage 0 0 0 >> MemtablePostFlusher 1 5 0 >> FILEUTILS-DELETE-POOL 0 0 0 >> FlushWriter 2 5 0 >> MiscStage 0 0 0 >> FlushSorter 0 0 0 >> InternalResponseStage 0 0 0 >> HintedHandoff 0 0 0 >> CompactionManager n/a 29 >> MessagingService n/a 0,34 >> >> On Sep 10, 2011, at 3:38 PM, Jeremy Hanna wrote: >> >>> We are experiencing massive writes to column families when only doing reads >>> from Cassandra. A set of 5 hadoop jobs are reading from Cassandra and then >>> writing out to hdfs. That is the only thing operating on the cluster. We >>> are reading at CL.QUORUM with hadoop and have written with CL.QUORUM. Read >>> repair chance is set to 0.0 on all column families. However, in the logs, >>> I'm seeing flush after flush of memtables and compactions taking place. Is >>> there something else that would be writing based on the above description? >>> >>> Jeremy >> > > -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
