Simulation and design of storage area network

Abstract

Storage systems researchers need Storage Area Network (SAN) simulation tool to develop and verify new ideas and algorithms for Fibre Channel (FC) storage area networks.Currently there are no simulation tools which can simulate the whole SAN environment. Most of the simulation studies and tools are only functional simulation tool, and have been very limited in modeling and simulation at the FC protocol level.In the thesis, SANSim, a new FC SAN simulation and design platform, is presented. SANSim is developed to aid the development and verification of the new ideas and algorithms for FC storage area networks. It supports FC frame-level simulation which fully simulates Fibre Channel protocols in accordance to the relevant standards to guarantee the compatibility and interoperability of different modules.SANSim includes four main modules: I/O workload module, host module, storage network module, and storage system module. I/O workload module generates I/O request streams according to the workload distribution characteristics and sends them to the host modules. Host module encapsulates the I/O workload to the Small Computer System Interface (SCSI) commands and sends them to the Host Bus Adaptor (HBA) sub-modules. Network module simulates the network connectivity, topology and communication mechanism. The FC network module includes three submodules: FC_controller module, FC_switch module and FC_communication module. Storage module maps I/O data to the storage devices.SANSim uses event driven simulation methodology. The SANSim simulation modules have been validated by comparing the simulation results with the actual I/O performance of a FC Random Access Memory (RAM) disk connected to a FC network. The results show that SANSim model is accurate with error range less than 3% for read operation, and less than 10% for write operation.SANSim can be used effectively in uncovering hidden protocol design problems in existing system. The Core/Edge FC implementation is a typical storage network structure in FC SAN network. How to design and optimize the FC network design is an important issue. The thesis also provides the detailed analysis of Core/Edge network performance matrix based on SANSim. The simulation results show that the Core/Edge topology suffers from certain level of bandwidth loss due to the Head-of-Line blocking caused by traffic crossing multi-stage switches.