What’s new in Cassandra 1.1: live traffic sampling

Cassandra 1.0 introduced two compaction strategies: SizeTieredCompactionStrategy and LeveledCompactionStrategy. Choosing between them can be challenging due to the dependence on application behavior and requirements. Testing compaction strategies is difficult as it requires re-compacting all data, which takes a long time and only allows static analysis. Cassandra 1.1 introduced write survey mode, allowing live traffic sampling to a test node without significantly impacting the existing cluster. This feature can be exploited for comparing compaction strategies by following specific steps. The ability to change compaction strategy via JMX ensures it's only changed on the test node. In the future, testing compression settings using this method is also planned.