Evaluating Backup Algorithms

We present a trace-driven simulator that evaluates the performance of backup algorithms. We use this simulator to compare the performance of the commonly-used level scheme (our name for the algorithm used by the UNIX dump utility) with that of a new algorithm called the Z scheme. We show that the Z scheme has better backup performance than the level scheme and slightly worse restore performance. We also show that the Z scheme consumes less media for backups than the level scheme.