基于iSCSI协议的虚拟磁盘的设计与实现

发布时间：2018-03-18 06:41

本文选题：虚拟块设备　切入点：自动精简配置　出处：《华中科技大学》2013年硕士论文　论文类型：学位论文

【摘要】：在基于iSCSI协议的分级存储系统中，客户端对存储资源的多次请求会在本地创建多个逻辑卷，热点数据的持续迁移也会产生越来越多的存储碎片，这将增大系统的管理难度，可靠性也随之降低。现有的客户端虚拟设备管理方法大多采用资源预留和静态分配策略，存储设备利用率很低，为了满足系统需求并实现存储资源的自动精简配置必须开发新的虚拟磁盘控制器。虚拟磁盘控制器通过位于块设备驱动层的虚拟设备映射模块实现，将各逻辑卷组织成一个统一的逻辑存储单元提供给文件系统使用，管理由于数据迁移产生的存储碎片；采用动态地址映射技术管理虚拟设备和通过iSCSI协议连接到本地的物理设备之间的映射关系，只有实际请求发生时才为虚拟块设备分配物理资源，从而实现自动精简配置；考虑到虚拟设备在重定向读写请求时需要频繁的读取映射表项，在查找过程中采用B-树算法来提高速率；虚拟设备映射模块中加入缓存并合并I/O操作的调度层，合并重定向到同一物理设备上相邻的读写操作，提高随机读写模式下虚拟磁盘的吞吐率。基于iSCSI协议实现了原型系统，测试表明，虚拟设备实现了统一管理逻辑卷和动态分配存储资源的功能；结果表明，顺序读写模式下性能基本无影响；随机读写模式下，本地虚拟磁盘的吞吐率提高了9%，网络虚拟磁盘吞吐率降低了11%。因此，虚拟磁盘能够在部分轻微牺牲系统性能的前提下提供所需功能。
[Abstract]:In the hierarchical storage system based on iSCSI protocol, multiple requests for storage resources by the client side will create multiple logical volumes locally, and the continuous migration of hot data will also produce more and more storage fragments, which will increase the management difficulty of the system. Most of the existing methods of client virtual device management adopt resource reservation and static allocation strategy, and the utilization of storage device is very low. A new virtual disk controller must be developed in order to meet the requirements of the system and realize the automatic configuration of storage resources. The virtual disk controller is implemented by the virtual device mapping module located in the block device driver layer. Each logical volume is organized into a unified logical storage unit to provide the file system for use, and the storage fragments caused by the data migration are managed. Dynamic address mapping technology is used to manage the mapping relationship between virtual devices and physical devices connected to local devices through iSCSI protocol. Only when the actual requests occur, physical resources are allocated for virtual block devices, so that the configuration can be reduced automatically. Considering that the virtual device needs to read the mapping table items frequently when it redirects the read and write request, the B- tree algorithm is used to improve the speed in the lookup process, and the scheduling layer of caching and merging I / O operations is added to the virtual device mapping module. Combined redirection to adjacent read and write operations on the same physical device to improve the throughput of virtual disks in random read and write mode. The prototype system is implemented based on iSCSI protocol. The test results show that the virtual device realizes the functions of unified management of logical volumes and dynamic allocation of storage resources. The throughput of the local virtual disk has increased by 9%, and the throughput of the network virtual disk has been reduced by 11%. Therefore, the virtual disk can provide the required function at the slight expense of system performance.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333.3

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