REMOTE DUPLICATE DATABASED FACILITY WITH TRIPLE CONTINGENCY PROTECTION

A primary computer system has a database, application programs that modify the local database, and a transaction manager that stores audit records in a local audit trail reflecting those application program modifications to the local database. A plurality of parallel backup systems are used to provide "triple contingency protection" of the data on the primary computer system. However, if the primary system suffers a sudden catastrophic failure, the parallel backup systems will generally be left in inconsistent states. To restart the application programs on one of the backup system, the parallel backup are first synchronized with each other, and then transaction processing is restarted with one of the backup systems as the new primary system, and the other backup systems as the backups to the new primary system. In addition, in order to enable any single backup system's database to be brought into a self consistent state, backup volume Updaters are stopped after database updates for all transactions committed on the primary system before a specified time have been completely applied to the backup system's database. After any reports requiring a self consistent database have been generated, operation of the Updaters is resumed.