本文關(guān)鍵詞： 高可用 虛擬化 鏡像內(nèi)存　出處：《上海交通大學(xué)》2013年碩士論文　論文類型：學(xué)位論文

【摘要】：云計(jì)算集群的規(guī)模正日益增大，對(duì)可用性要求也越來(lái)越高。文獻(xiàn)顯示對(duì)于商業(yè)云計(jì)算公司而言，每分鐘的宕機(jī)可能造成數(shù)萬(wàn)美元的損失。然而最近的研究表明在大規(guī)模云計(jì)算環(huán)境下，每年約有32%的機(jī)器會(huì)出現(xiàn)內(nèi)存錯(cuò)誤，更有1.3%的機(jī)器會(huì)因此導(dǎo)致機(jī)器重啟或者數(shù)據(jù)異常。內(nèi)存錯(cuò)誤在大規(guī)模集群中，可以被認(rèn)為是一種常態(tài)化的現(xiàn)象，因此提升內(nèi)存的可用性在今天變得越發(fā)重要。 傳統(tǒng)的內(nèi)存可用性提升方式可以分為硬件方式和軟件方式。硬件方式包括鏡像內(nèi)存與ECC內(nèi)存，這兩類技術(shù)都需要特殊的硬件支持。軟件方式也可分為兩類,一類從應(yīng)用層對(duì)關(guān)鍵數(shù)據(jù)進(jìn)行備份，，另一類方式使用虛擬化技術(shù)對(duì)整機(jī)進(jìn)行備份，這些方式性能相對(duì)較為低下。 本論文希望以軟件方式實(shí)現(xiàn)鏡像內(nèi)存系統(tǒng)，它將為內(nèi)存中的原空間創(chuàng)建出相應(yīng)的備份空間，供備份數(shù)據(jù)存儲(chǔ)。本論文分別在兩套獨(dú)立的層面實(shí)現(xiàn)上述功能：一種是基于操作系統(tǒng)層、輕量、高效的備份空間創(chuàng)建，即Memv6；另一種是基于虛擬化技術(shù)、對(duì)操作系統(tǒng)透明的Memvisor。 在Memv6中，通過修改操作系統(tǒng)的內(nèi)存管理模塊，使得在創(chuàng)建原頁(yè)表時(shí)，同步地創(chuàng)建備份頁(yè)表，從而完成備份空間的建立。此外，為了保證原空間的地址范圍與備份空間的地址范圍不產(chǎn)生沖突，本論文分析了操作系統(tǒng)中的內(nèi)存布局，并對(duì)原始布局進(jìn)行了相應(yīng)修改，保證了系統(tǒng)的正確性。 Memvisor使用虛擬化技術(shù)完成了類似功能。通過修改直接頁(yè)表技術(shù)中的頁(yè)表創(chuàng)建流程，或者修改影子頁(yè)表技術(shù)中的頁(yè)表翻譯流程，完成備份空間的創(chuàng)建。虛擬化技術(shù)可以屏蔽操作系統(tǒng)對(duì)備份空間創(chuàng)建的可見性，增大了應(yīng)用范圍。此外，它也允許在一個(gè)物理機(jī)上同時(shí)運(yùn)行高可用虛擬機(jī)和非高可用虛擬機(jī)，相比硬件高可用方案更為靈活。 實(shí)驗(yàn)顯示，所有的原空間都成功創(chuàng)建了相應(yīng)的備份空間，一個(gè)200KB的備份空間創(chuàng)建所需的額外時(shí)間少于1毫秒，對(duì)于xv6命令的性能影響為5%-8%，對(duì)小型Web服務(wù)器thttpd性能影響小于5%。相較于其他軟件高可用技術(shù)，其造成的性能影響僅為它們的5%~10%。
[Abstract]:Cloud computing clusters are growing in size and demand for availability. The literature shows that for commercial cloud computing companies, Downtime per minute can cost tens of thousands of dollars. But recent research shows that about 32% machines in large-scale cloud computing suffer from memory errors each year. More than 1.3% machines can cause machine restarts or data anomalies. Memory errors can be considered a regular phenomenon in large clusters, so improving memory availability is becoming more and more important today. The traditional methods of improving memory availability can be divided into hardware mode and software mode. Hardware mode includes mirrored memory and ECC memory, both of which require special hardware support. One is to backup critical data from the application layer, the other is to use virtualization technology to back up the whole machine. These methods have relatively low performance. This paper hopes to realize the mirror memory system by software, which will create the corresponding backup space for the original space in the memory. This paper implements the above functions in two independent layers: one is based on the operating system layer, light, efficient backup space creation, that is Memv6; the other is based on virtualization technology, transparent to the operating system Memvisor. In Memv6, the backup page table is created synchronously when the original page table is created by modifying the memory management module of the operating system. In order to ensure that there is no conflict between the address range of the original space and the address range of the backup space, this paper analyzes the memory layout in the operating system, and modifies the original layout to ensure the correctness of the system. Memvisor uses virtualization to do this by modifying the page table creation process in the direct page table technology, or by modifying the page table translation process in the shadow page table technology. Virtualization technology can mask the visibility of the operating system to create backup space and increase the scope of application. In addition, it also allows to run both highly available and non-highly available virtual machines on a physical machine. It is more flexible than the hardware high availability scheme. The experiment shows that all the original spaces have been successfully created, and the extra time required to create a 200KB backup space is less than 1 millisecond. The performance effect of the xv6 command is 5- 8, and the effect on the thttpd performance of the small Web server is less than 50.Compared with other highly available software technologies, the performance impact is only 510% of them.
【學(xué)位授予單位】：上海交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：TP333;TP309.3

【共引文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 孫韋;基于二進(jìn)制代碼注入框架的內(nèi)存?zhèn)浞輀D];上海交通大學(xué);2013年

本文編號(hào)：1509270