Imperial College London
The authors present and validate an enhanced analytical queuing network model of zoned RAID. The model focuses on RAID levels 01 and 5, and yields the distribution of I/O request response time. Whereas their previous paper could only support arrival streams of I/O requests of the same type, the model presented here supports heterogeneous streams with a mixture of read and write requests. This improved realism is made possible through multiclass extensions to their existing model. When combined with priority queuing, this development also enables more accurate modeling of the way subtasks of RAID 5 write requests are scheduled.