本文選題：計(jì)算系統(tǒng)虛擬化　切入點(diǎn)：磁盤I/O　出處：《華中科技大學(xué)》2012年碩士論文　論文類型：學(xué)位論文

【摘要】：在以機(jī)械磁盤為存儲(chǔ)介質(zhì)的計(jì)算機(jī)系統(tǒng)中，數(shù)據(jù)讀寫操作的效率和可靠性將直接影響整個(gè)計(jì)算機(jī)系統(tǒng)的性能和穩(wěn)定性。為了在存儲(chǔ)介質(zhì)的讀寫速度、容量以及成本價(jià)格方面做出權(quán)衡，現(xiàn)代計(jì)算機(jī)操作系統(tǒng)一般采取了以高速緩存、內(nèi)存以及機(jī)械磁盤所組成的三級(jí)存儲(chǔ)結(jié)構(gòu)，操作系統(tǒng)會(huì)在內(nèi)存中專門開辟出一塊空間作為磁盤緩存。在這種結(jié)構(gòu)中，磁盤數(shù)據(jù)寫操作的方法通常分為兩種：寫直達(dá)法和寫回法。如何在這兩種寫方法之間做出權(quán)衡以使得系統(tǒng)既具有較好的可靠性又具有較高的磁盤讀寫性能是一個(gè)亟待解決的問題。 基于開源虛擬化平臺(tái)Xen的內(nèi)存臟數(shù)據(jù)回寫系統(tǒng)(VWrite)利用計(jì)算機(jī)系統(tǒng)虛擬化環(huán)境的結(jié)構(gòu)特點(diǎn)和用戶使用習(xí)慣，實(shí)現(xiàn)了一種兼有寫直達(dá)法和寫回法優(yōu)點(diǎn)的磁盤數(shù)據(jù)寫操作的方法。此方法通過修改虛擬機(jī)塊設(shè)備前后端驅(qū)動(dòng)程序，在虛擬機(jī)管理器中為每個(gè)虛擬機(jī)建立塊級(jí)別的虛擬機(jī)磁盤緩存。虛擬機(jī)中的應(yīng)用程序均采取寫直達(dá)的方式，將數(shù)據(jù)直接寫到位于虛擬機(jī)管理器的虛擬機(jī)磁盤緩存中，當(dāng)虛擬機(jī)意外崩潰時(shí)，虛擬機(jī)管理器可以將對(duì)應(yīng)的虛擬機(jī)磁盤緩存上的數(shù)據(jù)寫入物理磁盤，以防止虛擬機(jī)數(shù)據(jù)的意外丟失。同時(shí)，與傳統(tǒng)寫直達(dá)方式不同的是，虛擬機(jī)中的應(yīng)用程序只需要將數(shù)據(jù)寫到磁盤緩存即可返回，無需等待數(shù)據(jù)被寫入慢速的物理磁盤，從而在保證虛擬機(jī)數(shù)據(jù)完整性的情況下大幅度提高了傳統(tǒng)寫直達(dá)法的效率。另外，此系統(tǒng)還做了以下工作來進(jìn)一步提高虛擬機(jī)磁盤I/O的性能：在虛擬機(jī)管理器中選擇合適的磁盤I/O調(diào)度算法以減小其對(duì)虛擬機(jī)磁盤I/O的性能影響；將虛擬機(jī)磁盤緩存中的請(qǐng)求進(jìn)行統(tǒng)一的排序和合并以提高虛擬機(jī)隨機(jī)磁盤I/O操作的性能；實(shí)現(xiàn)分時(shí)刷新策略以保證多個(gè)虛擬機(jī)對(duì)物理磁盤I/O帶寬的合理利用。 實(shí)驗(yàn)結(jié)果表明，，VWrite系統(tǒng)能兼有寫回法和寫直達(dá)法的優(yōu)點(diǎn)，能夠?yàn)樘摂M機(jī)提供高效率的磁盤讀寫操作，同時(shí)，在虛擬機(jī)系統(tǒng)突然宕機(jī)時(shí)也能保證其用戶數(shù)據(jù)的完整性和可靠性。
[Abstract]:In computer system with mechanical disk as storage medium, the efficiency and reliability of data read-write operation will directly affect the performance and stability of the whole computer system. In terms of capacity and cost, modern computer operating systems typically use a three-tier storage structure consisting of cache, memory, and mechanical disks. The operating system creates a special piece of space in memory for disk caching. In this structure, There are usually two ways to write disk data: write direct and write back. How to make a trade-off between these two writing methods so that the system has better reliability and higher disk read and write performance is a. An urgent problem. Based on the open source virtualization platform Xen, the memory dirty data write-back system (VWrite3) utilizes the structural characteristics of the virtualization environment of computer system and the usage habits of users. In this paper, a method of disk data writing with both the advantages of write direct method and write back method is implemented, which modifies the driver of the front and rear end of the virtual machine block device. Create a block level virtual machine disk cache for each virtual machine in the virtual machine manager. Applications in the virtual machine write the data directly to the virtual machine disk cache located in the virtual machine manager. When the virtual machine crashes unexpectedly, the virtual machine manager can write the data on the corresponding virtual machine disk cache to the physical disk to prevent the accidental loss of the virtual machine data. An application in a virtual machine simply writes the data to the disk cache and returns it without waiting for the data to be written to a slow physical disk. In order to ensure the integrity of the virtual machine data, greatly improve the efficiency of the traditional write direct method. The system also does the following work to further improve the performance of the virtual machine disk I / O: select the appropriate disk I / O scheduling algorithm in the virtual machine manager to reduce its impact on the virtual machine disk I / O performance; In order to improve the performance of random disk I / O operation in virtual machine, the request in virtual machine disk cache is sorted and merged uniformly, and a time-sharing refresh strategy is implemented to ensure the reasonable utilization of physical disk I / O bandwidth by multiple virtual machines. The experimental results show that the VWrite system has the advantages of both write-back and write-direct, and can provide high efficiency disk read and write operation for virtual machine. At the same time, the integrity and reliability of user data can be guaranteed when the virtual machine system goes down suddenly.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2012
【分類號(hào)】：TP333.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 朱智林,左天軍,牛淑齡;基于日志的臟數(shù)據(jù)檢測(cè)與恢復(fù)[J];電子科技;2004年05期

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