Some of Hadoop essential persistent data stuctures explained (
SequenceFile provides a persistent data structure for binary key-value pairs. In contrast with other persistent key-value data structures like B-Trees, you can’t seek to a specified key editing, adding or removing it. This file is append-only.
On the topic of persistent data structures, you might also take a look at this comparison of B+trees, LSM trees, and Fractal trees.
Original title and link: Hadoop I/O: Sequence, Map, Set, Array, BloomMap Files (NoSQL databases © myNoSQL)