SizeTieredCompactionStrategy (STCS): The default compaction strategy. This strategy triggers a minor compaction when there are a number of similar sized SSTables on disk as configured by the table subproperty, min_threshold. A minor compaction does not involve all the tables in a keyspace. Also see STCS compaction subproperties.

DateTieredCompactionStrategy (DTCS) (deprecated).

TimeWindowCompactionStrategy (TWCS): This strategy is an alternative for time series data. TWCS compacts SSTables using a series of time windows. While with a time window, TWCS compacts all SSTables flushed from memory into larger SSTables using STCS. At the end of the time window, all of these SSTables are compacted into a single SSTable. Then the next time window starts and the process repeats. The duration of the time window is the only setting required. See TWCS compaction subproperties. For more information about TWCS, see /architecture/database-internals/how-data-maintain.html[How is data maintained?].

LeveledCompactionStrategy (LCS): The leveled compaction strategy creates SSTables of a fixed, relatively small size (160 MB by default) that are grouped into levels. Within each level, SSTables are guaranteed to be non-overlapping. Each level (L0, L1, L2 and so on) is 10 times as large as the previous. Disk I/O is more uniform and predictable on higher than on lower levels as SSTables are continuously being compacted into progressively larger levels. At each level, row keys are merged into non-overlapping SSTables in the next level. This process can improve performance for reads, because the database can determine which SSTables in each level to check for the existence of row key data. This compaction strategy is modeled after Google’s LevelDB implementation. Also see LCS compaction subproperties.