Distributed Storage Cluster Design for Remote Mirroring Based on Storage Area Network

With the explosion of information nowadays, applying data storage safety requirements has become a new challenge, especially in high data available cluster environments. With the emergence of Storage Area Networks （SANs）, storage can be network-based and consolidated, and mass data movements via Fiber Channels （FCs） can be of very high speed. Based on these features, this paper introduces a dual-node storage cluster designed for remote mirroring as a concurrent data replication method to protect data during system failures. This design takes full advantage of a SAN system＇s benefits, and it adopts a synchronous protocol to guarantee a fully up-to-date data copy on the remote site. By developing a Linux kernel module to control the I/O flow and by using the technologies of software Logic Unit Number （LUN） masking, background online resynchronization and a self-management daemon, we have achieved a reliable mirroring system with the characteristics of server-free data replication, fault tolerance, online disaster recovery and high performance. In this study, we implemented the design in a remote mirror subsystem built on a software Fiber Channel Storage Area Network （FC-SAN） system.

Security System in United Storage Network and Its Implementation

With development of networked storage and its applications, united storage network (USN) combined with network attached storage (NAS) and storage area network (SAN) has emerged. It has such advantages as high performance, low cost, good connectivity, etc. However the security issue has been complicated because USN responds to block I/O and file I/O requests simultaneously. In this paper, a security system module is developed to prevent many types of attacks against USN based on NAS head. The module not only uses effective authentication to prevent unauthorized access to the system data, but also checks the data integrity. Experimental results show that the security module can not only resist remote attacks and attacks from those who has physical access to the USN, but can also be seamlessly integrated into underlying file systems, with little influence on their performance.

Design of Enterprise Storage Architecture for Optimal Business Continuity

This paper presents a solution for optimal business continuity, with storage architecture for enterprise applications, which will ensure zero data loss and quick recovery. The solution makes use of Internet protocol storage area network （IPSAN）, which is used for data management without burdening the application server, as well as mix of synchronous and semi-synchronous replication techniques to replicate data to remote disaster recovery site. We have presented the detailed design of both synchronous and semi-synchronous with case study of using open source database postgres to prove our point for optimal business continuity. The theoretical presentation is also given for the same.

Design and Implementation of a Storage Virtualization System Based on SCSI Target Simulator in SAN

The ideal storage virtualization system is compatible with all operating systems in storage area networks (SANs). However, current storage systems on clustered hosts and multiple operating systems are not practical. This paper presents a storage virtualization system based on a SCSI target simulator in a SAN to solve these problems. This storage virtualization system runs in the target hosts of the SAN, dynamically stores the physical information, and uses the mapping table method to modify the SCSI command addresses. The system uses the bitmap technique to manage the free space. The storage virtualization system provides various functions, such as logical volume resizing, data mirroring, and snapshots, and is compatible with clustered hosts and multiple operating systems, such as Windows NT and RedHat.

Design and Implementation of SCSI Target Emulator

A SCSI target emulator is used in a storage area network （SAN） environment to simulate the behavior of a SCSI target for processing and responding to I/O requests issued by initiators. The SCSI target emulator works with general storage devices with multiple transport protocols. The target emulator utilizes a protocol conversion module that translates the SCSI protocols to a variety of storage devices and implements the multi-RAID-level configuration and storage visualization functions. Moreover, the target emulator implements RAM caching, multi-queuing, and request merging to effectively improve the I/O response speed of the general storage devices. The throughput and average response times of the target emulator for block sizes of 4 KB to 128 KB are 150% faster for reads and 67% faster for writes than the existing emulator. With a block size of 16 KB, the I/O latency of the target emulator is only about 20% that of the existing emulator.

SCSI Target Simulator Based on FC and IP Protocols in TH-MSNS

Storage area networks （SAN） generally use fiber channel （FC） disks, but they are expensive, hard to scale, and incompatible with previous storage arrays. This paper describes an SCSI interface disk array, which is controlled by a simulated target controller, as the target device of an SAN system. A detailed target- mode SCSI middle level design and implementation is described with interfaces to efficiently supervise the entire target simulator. The target simulator has control flexibility, wide applicability, reduced SAN system cost, and compatibility with current SAN systems. The present mass data storage system uses a 2-Gb/s fiber network. Performance and compatibility tests demonstrate the efficiency of the target simulator design.

Design and Implementation of a Fibre Channel Target Driver Supporting SCSI

Fibre channel storage area networks (FC-SAN) are effective solutions to address storage man- agement problems caused by very large volumes of data. But the expense of fibre channel devices limits FC-SAN applications. The use of IP networks instead of fibre channel networks will reduce SAN cost, but will also reduce the performance. Therefore, small computer system interface (SCSI) devices were consid- ered to replace FC disks to reduce the SAN cost. A driver for the FC network adapter and the FC target, de- signed and implemented to support this structure, obeys the SCSI protocol and works in target mode with 200 MB/s bandwidth. The FC target architecture and implementation were compared with the FC initiator. The SCSI command transfer process in the FC layer was described. The performance test results show that the maximum I/O throughput reachs 167 MB/s for read requests and 196 MB/s for write requests (FC band- width is 200 MB/s), verifying that the FC target is very efficient. The modularization, efficiency, and low cost of the FC target will enable SAN and fibre channel to be more widely used in applications.