/3 𝐋𝐒𝐌-𝐓𝐫𝐞𝐞
LSM-Tree (Log-Structured Merge Tree) is widely used by many NoSQL databases, such as Cassandra, LevelDB, and RocksDB.
LSM-trees maintain key-value pairs and are persisted to disk using a Sorted Strings Table (SSTable), in which the keys are sorted.