The RAID5x is a two-disk failure-tolerant scheme of disk array that can be moved to the distributed environments. This new scheme called RAID5x variation can guarantees fault tolerance both to double node and double disk failures, there are two variations based on data distribution for placing data, parity, and mirrored copies within a periodical stripe: disk clustering and disk de-clustering. Then this paper analyzed the reliability of this system by combination of fuzzy logic and Markov modeling. This reliability method is a technique for analyzing fault tolerant designs under considerable uncertainty, such as is seen in compilations of component failure rates, the presented model provides the estimation of the lower and upper boundary of RAID5x variation with a single run of the model.