Roll-forward and rollback recovery: performance-reliability trade-off

Performance and reliability trade-offs depend on the recovery scheme used in any fault-tolerant system. Gain in performance, using comparable resources, typically requires sacrifice in reliability, and vice-versa. Roll-forward schemes for duplex systems achieve better performance than rollback schemes, without a significant increase in hardware resource requirements. This paper compares two roll-forward schemes with two roll-back schemes. It is shown that the roll-forward schemes improve performance with only a small loss in reliability as compared to rollback schemes.