Research On Ethernet-Based Storage System

With the development of hardware technologies, computer architecture has had great changes. The centre of computer system is transferring from traditional CPU, memory and network to storage system. Meeting the requirement, networking storage system is making progress speedly, particularily, emerging of Ethernet-base storage system make it possible to populize broadly. Cluster is the main architecture in parallel computing, it generally employs SAN-based networking storage system. Because of too high TCO of SAN-based storage system, cluster hasn't been deployed widely. It is very significant to study Ethernet-based storage system in cluster environment.Currently, Ethernet-based storage system is based on iSCSI protocol which uses TCP transport protocol. Through evaluating and analyzing the performance of iSCSI system over TCP, we discover that TCP cannot satisfy the special need of storage system, it leads to low transferring performance and high CPU utilization. Overhead on processing transport protocol lowers the system performance, so improving transport protocol performance will help to increase the performance of iSCSI storage system.In order to improve iSCSI transfer, we put forward a new transport protocol named HSP which aims at iSCSI storage system in Ethernet environment. HSP uses simplified protocol stack, it employs the service provided by data link to transmit data. And HSP uses a new flow control method which is based on data group window, in this way HSP can transmit more data in one transport process. HSP also employs some mechanisms including acknowledge and data retransmission based on timer, and dynamic time alternation to avoid the occurrence of network congestion effectively. It also uses progressive acknowledge and selective resending so as to reach more bandwidth utilization. In addition, HSP provides data security including authentication and data encryption.As a modeling method, CPN is widely adopted in describing and verifying distributed system, concurrent system and protocol. In order to verify HSP data transmitting process, we use CPN to describe HSP data transmission. After modeling HSP transmission with CPN, we verify the model using software tool Design/CPN, the result shows that HSP can transmit data correctly.After analyzing the architecture of Linux OS network subsystem, we present the implementation method of HSP protocol, and we also implement HSP protocol module under Linux. We make preliminary evaluation and analysis. Compared with TCP, under storage environment which have bulk data transmission, HSP can obtain more performance, its utilization of physical network bandwidth exceed 90 percent. We also run the iSCSI software over HSP protocol and test its performance, the result shows that is better than TCP.