1、Acegene IT Co. Ltd.,1,Linux操作系統(tǒng) 簡介,周炯 上海艾基信息技術(shù)有限公司,Acegene IT Co. Ltd.,2,內(nèi)容提要,Linux簡介 Linux的安裝 SHELL及常用程序 文件編輯器vi 目錄和文件管理 文件系統(tǒng)管理 用戶管理,網(wǎng)絡(luò)管理 網(wǎng)絡(luò)文件系統(tǒng) 模塊安裝和配置 系統(tǒng)管理 系統(tǒng)優(yōu)化 開發(fā)工具 Internet管理,Acegene IT Co. Ltd.,3,Linux簡介,Linux操作系統(tǒng)是可以運(yùn)行在許多不同類型的計(jì)算機(jī)上的一種操作系統(tǒng)的“內(nèi)核”。它是提供命令行或者程序與計(jì)算機(jī)硬件之間接口的軟件的核心部分。Linux操作系統(tǒng)內(nèi)核管理以下事情：比如內(nèi)

2、存、采用什么方法以及在什么時(shí)候打開或者關(guān)閉文件、哪一個(gè)進(jìn)程或者程序可以獲得計(jì)算機(jī)的中央處理單元(CPU)等等。 Linux操作系統(tǒng)可以說是UNIX操作系統(tǒng)的一個(gè)克隆體，它最初是在1991年10月5日由它的作者Linus Torvalds于赫爾辛基大學(xué)發(fā)布的。,Acegene IT Co. Ltd.,4,Linux功能,所有主要的網(wǎng)絡(luò)協(xié)議 硬盤配額支持 全部的源代碼 國際化的字體和鍵盤 作業(yè)控制 數(shù)學(xué)協(xié)處理器仿真 內(nèi)存保護(hù) 多平臺,多處理器 多用戶 多任務(wù) 共享的庫文件 支持多種文件系統(tǒng) 虛擬控制臺 虛擬內(nèi)存 其他更多功能,Acegene IT Co. Ltd.,5,GPL和Free,Linux

3、操作系統(tǒng)遵從GNU公共許可證（ GNU Public License，簡稱GPL）的規(guī)定。 Linux對外的一個(gè)重要的特點(diǎn)就是”Free”，自由和免費(fèi)。,Acegene IT Co. Ltd.,6,What is Linux?,Linux is an operating system with the following attributes: Multi-user Multi-tasking Virtual memory system X-Windows Compatible with the IEEE POSIX.1 standard Non-proprietary source code

4、 Source code is available,Acegene IT Co. Ltd.,7,Is Linux the same as UNIX?,The command set is similar They work the same They look the same Linux cannot use the UNIX trademark Linux is essentially UNIX,Acegene IT Co. Ltd.,8,Is Linux a real OS?,Yes, absolutely Linux is used In mission critical applic

5、ations Around the world There are many flavors of Linux available We call them: Distributions,Acegene IT Co. Ltd.,9,Linux發(fā)行版本的概念,大多數(shù)的Linux操作系統(tǒng)的發(fā)行版本都使用標(biāo)準(zhǔn)的Linux內(nèi)核，但有時(shí)候也會稍微加以修改，這個(gè)操作系統(tǒng)現(xiàn)在的規(guī)模已經(jīng)變得相當(dāng)龐大了，因此許多人更愿意購買一張它的CD-ROM光盤。每一種發(fā)行版本彼此之間都稍微有一些差異，這些差異主要表現(xiàn)在它們各自的安裝程序包上，還表現(xiàn)在安全性與可用性等方面?zhèn)戎攸c(diǎn)的不同。把系統(tǒng)內(nèi)核、附帶的工具程序及應(yīng)用軟件包等

6、等打包在一起，這樣組成的一個(gè)Linux操作系統(tǒng)的集合體就是我們說的某一種發(fā)行版本。,Acegene IT Co. Ltd.,10,誰使用Linux操作系統(tǒng),Linux正在逐漸贏得普通用戶的青睞。但是它仍然不是一個(gè)適用于普通大眾的操作系統(tǒng)。對那些習(xí)慣了當(dāng)今鼠標(biāo)界面操作系統(tǒng)的人們來說， 學(xué)習(xí)仍是很困難的。需要學(xué)習(xí)一大套從未接觸過的命令，還需要學(xué)習(xí)與長期形成的概念不相同的那些對待與處理事情的方法。對那些具有UNIX操作系統(tǒng)使用經(jīng)驗(yàn)的人們來說，Linux可是容易多了。 專業(yè)用戶、系統(tǒng)管理員和計(jì)算機(jī)開發(fā)人員通常都會比一般的用戶更容易掌握Linux操作系統(tǒng)。但就是對這些人來說，這方面的學(xué)習(xí)與實(shí)踐也需要有足

7、夠的耐心與專心。,Acegene IT Co. Ltd.,11,Enterprise vs. Retail,Retail distributions Faster release cycles (4-6 months) Geared for home/productivity users Shorter support lifetimes Examples: RHL9, SuSE Linux 9 Enterprise level distributions Slower release cycles (12-18 months) Longer support lifetimes (3-5 ye

8、ars) Examples: RHEL3/4, SLES9 Adds performance and scalability enhancements,Linux Distribution Overview,The core parts of a Linux system are: Linux kernel User space utilities and applications The kernel and user space programs together make up the complete operating system,Linux Kernel,Core compone

9、nt of the operating system Configurable and tunable Provides main OS functions I/O, disk, network, etc. CPU Scheduling Memory management uname -r shows the kernel version number:,# uname -r 2.4.9-e.25,Acegene IT Co. Ltd.,14,Kernel concepts,Linux is based on a modular non-microkernel architecture All

10、 device drivers share the same memory with the kernel Device drivers are modular and can be loaded/unloaded dynamically Linux is multi-tasking Linux is a virtual-memory OS Most kernel parameters can be modified on the fly,All components of the operating system are delivered via RPM packages Kernel S

11、ystem utilities Applications Both Red Hat and SLES8 distributions use the RPM Package Manager (RPM) Originally named “Red Hat Package Manager”,Software Packages,Linux Updates,Apply the recommended updates by the distribution vendor: Most vendors provide automatic updates Red Hat Network supplies upd

12、ates automatically up2date SuSE uses YaST2 (Yet Another Setup Tool 2) you (YaST Online Update),Linux Enterprise Features,Linux enterprise features support : Performance Scalability Reliability,Acegene IT Co. Ltd.,18,Symmetric Multiprocessing,Fully multiprocessor capable (SMP) RHEL3: 16 processors SL

13、ES8: 32 processors Uniprocessor configuration supported on both Intel Hyperthreading (HT) enabled on IA-32 Physical-to-logical CPU affinity scheduling,Acegene IT Co. Ltd.,19,Improved Memory Utilization,Use more than 4GB of RAM on IA-32 RHEL 2.1: max 16GB supported RHEL3: max 64GB supported SLES8: up

14、 to 64GB supported Some older drivers not capable of accessing more than 4GB of RAM May perform “bounce buffering” to compensate Usually not a concern for enterprise-class drivers Kernel memory used more efficiently than before Run more processes without swapping,Acegene IT Co. Ltd.,20,Virtual Memor

15、y,Each process has a private address space Keeps private data in memory secure Prevents inter-process data corruption Contiguous view of memory Demand-based paging Pages are “swapped” out when low on RAM Pages are “swapped” in when accessed again Allows the system to use more memory than any single

16、space can address,Virtual Filesystem (VFS),Linux supports multiple file systems OS is file system independent Multiple file systems can be used simultaneously Cross-platform compatibility Performance VFS provides a single filesystem interface,Acegene IT Co. Ltd.,22,Filesystems,Important ones to know

17、: ext2/3 - Red Hat default (ext3) reiserfs - SLES8 default NFS - Network Filesystem Procfs - kernel virtual filesystem ISO 9660 (CD-ROM) OCFS - Oracle Cluster Filesystem ext2/3 and reiserfs are the most common Use OCFS instead of raw devices in RAC,Acegene IT Co. Ltd.,23,Filesystem Cache,Buffers all

18、 filesystem I/O All filesystem I/O is copied to/from cache buffers By default, writes are not immediately flushed Hardware I/O is deferred Reads benefit from previous accesses as well as automatic read-ahead May not need to perform a real hardware I/O Made up of page cache and buffer cache Page cach

19、e tends to be more heavily used Reduced automatically when low on RAM,Acegene IT Co. Ltd.,24,Process,Disk file,Write,Read,Raw Devices,Have traditionally been considered the high performance solution Bypasses the filesystem buffer cache Moves larger buffers than file system I/Os Requires more experie

20、nced administration,Acegene IT Co. Ltd.,25,Modular Drivers,Loadable kernel modules (LKM) Can be unloaded/reloaded without rebooting Modules provide: Device drivers File system drivers System calls Network drivers Executable interpreters Terminal device (TTY) drivers,I/O Modes,Disk I/O can be perform

21、ed in several different modes Asynchronous vs. synchronous Direct vs. buffered,Acegene IT Co. Ltd.,27,Storage Infrastructure,Direct-attached storage (DAS) IDE, SCSI e.g., LSI Megaraid Network-Attached Storage (NAS) NFS e.g., Network Appliance Filer Storage Area Networks (SAN) FibreChannel e.g., EMC

22、Clariion,Acegene IT Co. Ltd.,28,Linux Clusters,Scalable Shared Storage SCSI, SAN (FibreChannel), Firewire (devel.) Must use raw devices or OCFS Network Attached Storage (NFS) LVM and software RAID (“md”) not cluster-aware Linux includes cluster management software,Acegene IT Co. Ltd.,29,Linux Kernel Enhancements,Performance Asynchronous I/O Eliminate kernel locks Large SGA: 4 GB Support more Oracle users Stability Graceful degradation under load Manageability (Remote) Crash Dump Facility Configurat