ARIES recovers from a system crash in three passes.

Analysis pass: This pass determines which transactions to undo, which pages were dirty at the time of the crash, and the LSN from which the redo passshould start.

Redo pass: This pass starts from a position determined during analysis, and performs a redo, repeating history, to bring the database to a state it was in
before the crash. Undo pass: This pass rolls back all transactions that were incomplete at the time of crash.