Reliability Model of Fault-Tolerant Dual-Disk Redundant Array

This paper deals with data storage systems based on fault-tolerant dual-disk RAID-1, which are widely used as high-reliable data storage systems and have acceptable overhead expenses in hardware implementation. Advanced reliability model of dual-disk RAID-1 array based on Markov chains, which takes into consideration finite time of disk replacement after disk failure, different disk failure rate in array’s normal and rebuild states, and probability of read errors during array rebuild procedure, are also overviewed in this paper. Mathematical solution of reliability model, calculation formula for mean time to data loss, estimation of disk and array reliability parameters and MTTDL calculation example are also provided.