An efficient model for dimensioning an ATA-based virtual storage system

Internet Advanced Technology Attachment (iATA) is a block-level storage network protocol used by iATA servers to offer a storage solution for clients. With iATA, mobile users can access their valuable data through the network from anywhere and at anytime as if the storage device is attached locally. In the iATA architecture, iATA servers and iATA clients exchange necessary protocol messages over IP networks.This paper proposes an analytical queuing model based on quasi-birth-and-death (QBD) processes to evaluate the performability of an iATA server in a network environment. An exact solution method is developed and presented, however it has state space explosion problem. Therefore, we present a novel computational algorithm to approximate the performance measures. Comparison with numerical results obtained by the exact solution shows that the proposed algorithm is both accurate and fast.

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► A queuing model of iATA servers based on QBD processes in a network environment is proposed.
► In order to cope with this state space explosion, a new and computationally efficient approximate solution algorithm is developed.
► The proposed algorithm is both reasonably accurate and fast.
► It is also demonstrated that the approximate algorithm is numerically stable.