Performance analysis of the XDAC disk array system

The paper presents an analytical model of a whole disk array architecture, XDAC, which consists of several major subsystems and features: the two-dimensional array structure; IO-bus with split transaction protocol; and cache for processing multiple I/O requests in parallel. Our modelling approach is based on a subsystem access time per request (SATPR) concept, in which we model for each subsystem the mean access time per disk array request. The model is fed with a given set of representative workload parameters and then used to conduct performance analysis for exploring the impact of fork/join synchronization as well as evaluating some architectural design issues of the XDAC system. Moreover, by comparing the SATPRs of subsystems, we can identify the bottleneck for performance improvements.< >