Design And Implementation Of Concurrency Control Mechanism Of The High Performance ISCSI System

In the era of big data,the development of virtual machine technology presents new challenges to the performance of storage system.In the traditional storage system architecture,the storage device is provided with a small number of servers to provide storage services,and in the cloud computing virtualization environment,storage devices need to provide storage services for massive virtual machines.The upper application program of multi virtual machine is a concurrent access memory system,which makes the I/O present the characteristics of randomization and fragmentation,resulting in low performance of the storage system.In this paper,we have studied the concurrency of redundant disk array RAID and I/O,and reveal the deep reasons of the performance bottleneck of the existing storage system.On this basis,the design and implementation of a new SAN storage system,the performance of the existing system has been significantly improved.The main work of this paper is as follows:1)this paper reviews the development history of storage system,analyzes the characteristics and application scenarios of several important storage technologies,introduces several algorithms of data block,mainly from two aspects: single node and distributed.This paper studies the mapping mechanism of data block,data storage nodes and storage nodes.2)to study and research the performance of redundant disk array RAID5 in high concurrent access mode,the deep reasons of the performance bottleneck of the redundant disk array RAID5 are analyzed and revealed by the test of hardware RAID5 and software RAID5.3)the I/O model of the storage system is studied,and the existing four models are studied,which are synchronous,asynchronous and non blocking.4)an important open source software SCST,which is widely used and supported by iSCSI protocol,is analyzed.The function and interaction of SCST is analyzed.The SCST architecture is introduced from seven aspects: buffer management,device driver,target manager,etc.,and the mechanism of fileIO in scst_user is analyzed.5)based on the above research results,a set of high performance storage system is designed and implemented.The libaio,eventfd and other advanced features of Linux operating system are provided by the storage system.The high concurrency I/O programming model is implemented,and the data layout algorithm based on file partition is proposed in the disk management and data layout.6)for different block sizes and different access requests,a comprehensive test of the storage system is carried out.Tests show that the throughput and IOPS performance of the storage system designed in this paper are significantly higher than the existing system.