Disaster Recovery for Transaction Processing Systems (Thesis)

Abstract:

A remote backup is a copy of a primary database maintained at a
geographically separate location and is used to increase data
availability. Remote backup systems are usually log--based and can be
classified as either 2--safe or 1--safe, depending on whether
transactions commit at both sites simultaneously or the commit first
at the primary and are then propagated to the backup. This thesis
describes the 1--safe algorithms that can exploit multiple log streans
to propagate information from the primary to the backup. An
experimental distributed database system is used to evaluate the
performance of these algorithms and compare the 1--safe with the
2--safe approach under various conditions. Techniques for processing
read--only queries at the backup are also presented.