When to Use Leveled Compaction in Cassandra

The Leveled Compaction Strategy in Cassandra is designed to address the shortcomings of the Size-Tiered Compaction Strategy for certain use cases. It ensures that a row is spread across fewer SSTables, reducing read latencies and improving overall performance. However, it requires more I/O for compaction compared to size-tiered compaction. Leveled compaction may be beneficial when rows are frequently updated or if the application has strict latency requirements. It can also save disk I/O in certain scenarios. On the other hand, leveled compaction might not be suitable for write-heavy workloads and could worsen I/O issues if nodes cannot keep up with compaction. Testing with live traffic sampling is recommended before switching to leveled compaction. Additionally, using leveled compaction in combination with SSDs or when the entire dataset fits into memory can provide significant performance benefits.