Algorithms for the management of remote backup data bases for disaster recovery

A method for managing a remote backup database to provide protection from disasters that destroy the primary database is presented. The method is general enough to accommodate the ARIES-type recovery and concurrency control methods as well as the methods used by other systems such as DB2, DL/I and IMS Fast Path. It provides high performance by exploiting parallelism and by reducing inputs and outputs using different means, like log analysis and choosing a different buffer management policy from the primary one. Techniques are proposed for checkpointing the state of the backup system so that recovery can be performed quickly in case the backup system fails, and for allowing new transaction activity to begin even as the backup is taking over a primary failure. Some performance measurements taken from a prototype are also presented