Moving to Leveled compaction resolved same problem for us. As Robert mentioned, use it carefully. Size tiered compaction requires having 50% free disk space (also according to datastax documentation).
Pavel On Wed, Jul 9, 2014 at 8:39 PM, Robert Coli <rc...@eventbrite.com> wrote: > On Wed, Jul 9, 2014 at 4:27 PM, Andrew <redmu...@gmail.com> wrote: > >> What kind of overhead should I expect for compaction, in terms of size? >> In this use case, the primary use for compaction is more or less to clean >> up tombstones for expired TTLs. >> > > Compaction can result in output files >100% of the input, if compression > is used and the input SSTables are also compressed. If you use size tiered > compaction (STS), you therefore must have enough headroom to compact your > largest [n] SSTables together successfully. > > Level compaction (LCS) has a different, significantly lower, amount of > headroom. > > If you are making heavy use of TTL, you should be careful about using LCS > in certain cases, read : > > https://issues.apache.org/jira/browse/CASSANDRA-6654 - "Droppable > tombstones are not being removed from LCS table despite being above 20%" > > =Rob > >
