When the default compaction strategy the SSTables are grouped into buckets, where the size of every sstable int he bucket is within 50% of the average size of files in the bucket. There is also a catch all first bucket for all files less than 50MB (by default).
The min_compaction_threshold CF settings applies to the number of files in each bucket. So in your case you would have the following buckets: - 4 * 50MB - 1 * 100MB - 1 * 200MB It would compact the first bucket and create a file that would be in a bucket with one of the other two files. Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 24/01/2012, at 12:46 PM, Roshan wrote: > Hi > > We have deployed two node Cassandra 1.0.6 cluster to production and it > create SSTables on daily with different sizes. As I know, Cassandra will > compact 4 (as default compaction threshold) same size files identified by > compaction task. But every time in my system it identify 50MB 4 files and > compact it to some size (e.g. 200MB) SSTable by removing tombstones. But > next time it will compact 50MB 4 size file to another size (e.g. 100MB). If > the compact task create such different size files after removing tombstones, > some different size files are remain in system and not identified by > compaction task. > > I think major compaction using nodetool is not recommend for Cassandra 1.0.X > versions. So could you pelase advice me how to combine different size > SSTables together. Thanks. > > -- > View this message in context: > http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/SSTable-compaction-issue-in-our-system-tp7218239p7218239.html > Sent from the cassandra-u...@incubator.apache.org mailing list archive at > Nabble.com.
