26.2. 引​​​​​​​导​​​​​​​救​​​​​​​援​​​​​​​模​​​​​​​式​​​​​​​

Rescue mode provides the ability to boot a small Red Hat Enterprise Linux environment entirely from CD-ROM, or some other boot method, instead of the system's hard drive.

As the name implies, rescue mode is provided to rescue you from something. During normal operation, your Red Hat Enterprise Linux system uses files located on your system's hard drive to do everything — run programs, store your files, and more.

However, there may be times when you are unable to get Red Hat Enterprise Linux running completely enough to access files on your system's hard drive. Using rescue mode, you can access the files stored on your system's hard drive, even if you cannot actually run Red Hat Enterprise Linux from that hard drive.

要​​​​​​​进​​​​​​​入​​​​​​​救​​​​​​​援​​​​​​​模​​​​​​​式​​​​​​​，你​​​​​​​必​​​​​​​须​​​​​​​能​​​​​​​够​​​​​​​用​​​​​​​下​​​​​​​面​​​​​​​方​​​​​​​法​​​​​​​中​​​​​​​的​​​​​​​一​​​​​​​种​​​​​​​来​​​​​​​引​​​​​​​导​​​​​​​系​​​​​​​统​​​​​​​^[12]：

使​​​​​​​用​​​​​​​以​​​​​​​上​​​​​​​方​​​​​​​法​​​​​​​引​​​​​​​导​​​​​​​后​​​​​​​，把​​​​​​​ rescue 添​​​​​​​加​​​​​​​为​​​​​​​内​​​​​​​核​​​​​​​参​​​​​​​数​​​​​​​。​​​​​​​例​​​​​​​如​​​​​​​，对​​​​​​​于​​​​​​​ x86 系​​​​​​​统​​​​​​​，在​​​​​​​安​​​​​​​装​​​​​​​引​​​​​​​导​​​​​​​提​​​​​​​示​​​​​​​下​​​​​​​输​​​​​​​入​​​​​​​以​​​​​​​下​​​​​​​命​​​​​​​令​​​​​​​：

linux rescue

你​​​​​​​会​​​​​​​被​​​​​​​提​​​​​​​示​​​​​​​回​​​​​​​答​​​​​​​几​​​​​​​个​​​​​​​基​​​​​​​本​​​​​​​的​​​​​​​问​​​​​​​题​​​​​​​，包​​​​​​​括​​​​​​​要​​​​​​​使​​​​​​​用​​​​​​​的​​​​​​​语​​​​​​​言​​​​​​​。​​​​​​​它​​​​​​​还​​​​​​​提​​​​​​​示​​​​​​​你​​​​​​​选​​​​​​​择​​​​​​​有​​​​​​​效​​​​​​​救​​​​​​​援​​​​​​​映​​​​​​​像​​​​​​​的​​​​​​​位​​​​​​​置​​​​​​​。​​​​​​​从​​​​​​​ Local CD-ROM 、​​​​​​​Hard Drive、​​​​​​​NFS image、​​​​​​​FTP、​​​​​​​或​​​​​​​ HTTP 中​​​​​​​选​​​​​​​择​​​​​​​。​​​​​​​所​​​​​​​选​​​​​​​位​​​​​​​置​​​​​​​中​​​​​​​必​​​​​​​须​​​​​​​包​​​​​​​含​​​​​​​一​​​​​​​个​​​​​​​有​​​​​​​效​​​​​​​的​​​​​​​安​​​​​​​装​​​​​​​树​​​​​​​，这​​​​​​​个​​​​​​​安​​​​​​​装​​​​​​​树​​​​​​​里​​​​​​​的​​​​​​​Red Hat Enterprise Linux必​​​​​​​须​​​​​​​和​​​​​​​你​​​​​​​用​​​​​​​来​​​​​​​引​​​​​​​导​​​​​​​的​​​​​​​磁​​​​​​​盘​​​​​​​中​​​​​​​的​​​​​​​Red Hat Enterprise Linux版​​​​​​​本​​​​​​​相​​​​​​​同​​​​​​​。​​​​​​​如​​​​​​​果​​​​​​​你​​​​​​​使​​​​​​​用​​​​​​​一​​​​​​​个​​​​​​​引​​​​​​​导​​​​​​​光​​​​​​​盘​​​​​​​或​​​​​​​其​​​​​​​他​​​​​​​介​​​​​​​质​​​​​​​来​​​​​​​启​​​​​​​动​​​​​​​救​​​​​​​援​​​​​​​模​​​​​​​式​​​​​​​，这​​​​​​​个​​​​​​​安​​​​​​​装​​​​​​​树​​​​​​​必​​​​​​​须​​​​​​​和​​​​​​​创​​​​​​​建​​​​​​​介​​​​​​​质​​​​​​​所​​​​​​​用​​​​​​​的​​​​​​​安​​​​​​​装​​​​​​​树​​​​​​​相​​​​​​​同​​​​​​​。​​​​​​​关​​​​​​​于​​​​​​​如​​​​​​​何​​​​​​​在​​​​​​​硬​​​​​​​盘​​​​​​​驱​​​​​​​动​​​​​​​器​​​​​​​、​​​​​​​NFS 服​​​​​​​务​​​​​​​器​​​​​​​、​​​​​​​FTP 服​​​​​​​务​​​​​​​器​​​​​​​、​​​​​​​或​​​​​​​ HTTP 服​​​​​​​务​​​​​​​器​​​​​​​上​​​​​​​设​​​​​​​置​​​​​​​安​​​​​​​装​​​​​​​树​​​​​​​的​​​​​​​信​​​​​​​息​​​​​​​，请​​​​​​​参​​​​​​​阅​​​​​​​本​​​​​​​指​​​​​​​南​​​​​​​前​​​​​​​面​​​​​​​的​​​​​​​部​​​​​​​分​​​​​​​。​​​​​​​

如​​​​​​​果​​​​​​​你​​​​​​​选​​​​​​​择​​​​​​​的​​​​​​​救​​​​​​​援​​​​​​​映​​​​​​​像​​​​​​​不​​​​​​​需​​​​​​​要​​​​​​​网​​​​​​​络​​​​​​​连​​​​​​​接​​​​​​​，你​​​​​​​会​​​​​​​被​​​​​​​征​​​​​​​询​​​​​​​是​​​​​​​否​​​​​​​要​​​​​​​建​​​​​​​立​​​​​​​网​​​​​​​络​​​​​​​连​​​​​​​接​​​​​​​。​​​​​​​如​​​​​​​果​​​​​​​你​​​​​​​想​​​​​​​把​​​​​​​文​​​​​​​件​​​​​​​备​​​​​​​份​​​​​​​到​​​​​​​另​​​​​​​一​​​​​​​台​​​​​​​计​​​​​​​算​​​​​​​机​​​​​​​上​​​​​​​或​​​​​​​从​​​​​​​共​​​​​​​享​​​​​​​网​​​​​​​络​​​​​​​位​​​​​​​置​​​​​​​上​​​​​​​安​​​​​​​装​​​​​​​一​​​​​​​些​​​​​​​ PRM 软​​​​​​​件​​​​​​​包​​​​​​​时​​​​​​​，网​​​​​​​络​​​​​​​连​​​​​​​接​​​​​​​会​​​​​​​很​​​​​​​有​​​​​​​用​​​​​​​。​​​​​​​

下​​​​​​​面​​​​​​​的​​​​​​​信​​​​​​​息​​​​​​​将​​​​​​​显​​​​​​​示​​​​​​​：

The rescue environment will now attempt to find your Linux installation and mount it under the directory /mnt/sysimage. You can then make any changes required to your system. If you want to proceed with this step choose 'Continue'. You can also choose to mount your file systems read-only instead of read-write by choosing 'Read-only'. If for some reason this process fails you can choose 'Skip' and this step will be skipped and you will go directly to a command shell.

如​​​​​​​果​​​​​​​你​​​​​​​选​​​​​​​择​​​​​​​ Continue，它​​​​​​​会​​​​​​​试​​​​​​​图​​​​​​​把​​​​​​​你​​​​​​​的​​​​​​​文​​​​​​​件​​​​​​​系​​​​​​​统​​​​​​​挂​​​​​​​载​​​​​​​到​​​​​​​ /mnt/sysimage 目​​​​​​​录​​​​​​​下​​​​​​​。​​​​​​​如​​​​​​​果​​​​​​​它​​​​​​​挂​​​​​​​载​​​​​​​分​​​​​​​区​​​​​​​失​​​​​​​败​​​​​​​，它​​​​​​​会​​​​​​​通​​​​​​​知​​​​​​​你​​​​​​​。​​​​​​​如​​​​​​​果​​​​​​​你​​​​​​​选​​​​​​​择​​​​​​​ Read-Only，它​​​​​​​会​​​​​​​试​​​​​​​图​​​​​​​在​​​​​​​ /mnt/sysimage 目​​​​​​​录​​​​​​​下​​​​​​​挂​​​​​​​载​​​​​​​你​​​​​​​的​​​​​​​文​​​​​​​件​​​​​​​系​​​​​​​统​​​​​​​，但​​​​​​​是​​​​​​​挂​​​​​​​载​​​​​​​模​​​​​​​式​​​​​​​为​​​​​​​只​​​​​​​读​​​​​​​。​​​​​​​如​​​​​​​果​​​​​​​你​​​​​​​选​​​​​​​择​​​​​​​ Skip，你​​​​​​​的​​​​​​​文​​​​​​​件​​​​​​​系​​​​​​​统​​​​​​​将​​​​​​​不​​​​​​​会​​​​​​​被​​​​​​​挂​​​​​​​载​​​​​​​。​​​​​​​如​​​​​​​果​​​​​​​你​​​​​​​认​​​​​​​为​​​​​​​你​​​​​​​的​​​​​​​文​​​​​​​件​​​​​​​系​​​​​​​统​​​​​​​已​​​​​​​损​​​​​​​坏​​​​​​​，选​​​​​​​择​​​​​​​ Skip。​​​​​​​

一​​​​​​​旦​​​​​​​你​​​​​​​的​​​​​​​系​​​​​​​统​​​​​​​进​​​​​​​入​​​​​​​了​​​​​​​救​​​​​​​援​​​​​​​模​​​​​​​式​​​​​​​，在​​​​​​​ VC（虚​​​​​​​拟​​​​​​​控​​​​​​​制​​​​​​​台​​​​​​​）1和​​​​​​​ VC2（使​​​​​​​用​​​​​​​ Ctrl-Alt-F1 组​​​​​​​合​​​​​​​键​​​​​​​来​​​​​​​进​​​​​​​入​​​​​​​ VC1，Ctrl-Alt-F2 来​​​​​​​进​​​​​​​入​​​​​​​ VC2）上​​​​​​​会​​​​​​​出​​​​​​​现​​​​​​​提​​​​​​​示​​​​​​​：

sh-3.00b#

如​​​​​​​果​​​​​​​你​​​​​​​选​​​​​​​择​​​​​​​了​​​​​​​ Continue 来​​​​​​​自​​​​​​​动​​​​​​​挂​​​​​​​载​​​​​​​你​​​​​​​的​​​​​​​分​​​​​​​区​​​​​​​，并​​​​​​​且​​​​​​​它​​​​​​​们​​​​​​​被​​​​​​​成​​​​​​​功​​​​​​​地​​​​​​​挂​​​​​​​载​​​​​​​了​​​​​​​，那​​​​​​​么​​​​​​​你​​​​​​​就​​​​​​​会​​​​​​​进​​​​​​​入​​​​​​​单​​​​​​​用​​​​​​​户​​​​​​​模​​​​​​​式​​​​​​​。​​​​​​​

即​​​​​​​便​​​​​​​你​​​​​​​的​​​​​​​文​​​​​​​件​​​​​​​系​​​​​​​统​​​​​​​被​​​​​​​挂​​​​​​​载​​​​​​​，救​​​​​​​援​​​​​​​模​​​​​​​式​​​​​​​中​​​​​​​的​​​​​​​默​​​​​​​认​​​​​​​根​​​​​​​分​​​​​​​区​​​​​​​只​​​​​​​不​​​​​​​过​​​​​​​是​​​​​​​一​​​​​​​个​​​​​​​临​​​​​​​时​​​​​​​的​​​​​​​根​​​​​​​分​​​​​​​区​​​​​​​，而​​​​​​​不​​​​​​​是​​​​​​​正​​​​​​​常​​​​​​​用​​​​​​​户​​​​​​​模​​​​​​​式​​​​​​​（运​​​​​​​行​​​​​​​级​​​​​​​别​​​​​​​3或​​​​​​​5）中​​​​​​​的​​​​​​​文​​​​​​​件​​​​​​​系​​​​​​​统​​​​​​​根​​​​​​​分​​​​​​​区​​​​​​​。​​​​​​​如​​​​​​​果​​​​​​​你​​​​​​​选​​​​​​​择​​​​​​​要​​​​​​​挂​​​​​​​载​​​​​​​文​​​​​​​件​​​​​​​系​​​​​​​统​​​​​​​，并​​​​​​​且​​​​​​​它​​​​​​​被​​​​​​​成​​​​​​​功​​​​​​​地​​​​​​​挂​​​​​​​载​​​​​​​了​​​​​​​，你​​​​​​​可​​​​​​​以​​​​​​​通​​​​​​​过​​​​​​​执​​​​​​​行​​​​​​​以​​​​​​​下​​​​​​​命​​​​​​​令​​​​​​​来​​​​​​​把​​​​​​​救​​​​​​​援​​​​​​​模​​​​​​​式​​​​​​​的​​​​​​​根​​​​​​​分​​​​​​​区​​​​​​​改​​​​​​​变​​​​​​​为​​​​​​​你​​​​​​​的​​​​​​​文​​​​​​​件​​​​​​​系​​​​​​​统​​​​​​​的​​​​​​​根​​​​​​​分​​​​​​​区​​​​​​​：

chroot /mnt/sysimage

如​​​​​​​果​​​​​​​你​​​​​​​需​​​​​​​要​​​​​​​运​​​​​​​行​​​​​​​ rpm 之​​​​​​​类​​​​​​​的​​​​​​​命​​​​​​​令​​​​​​​，改​​​​​​​变​​​​​​​根​​​​​​​分​​​​​​​区​​​​​​​就​​​​​​​会​​​​​​​很​​​​​​​有​​​​​​​用​​​​​​​，因​​​​​​​为​​​​​​​这​​​​​​​类​​​​​​​命​​​​​​​令​​​​​​​要​​​​​​​求​​​​​​​你​​​​​​​的​​​​​​​根​​​​​​​分​​​​​​​区​​​​​​​被​​​​​​​挂​​​​​​​载​​​​​​​为​​​​​​​ /。​​​​​​​要​​​​​​​退​​​​​​​出​​​​​​​ chroot 环​​​​​​​境​​​​​​​，键​​​​​​​入​​​​​​​ exit，你​​​​​​​就​​​​​​​会​​​​​​​返​​​​​​​回​​​​​​​到​​​​​​​提​​​​​​​示​​​​​​​。​​​​​​​

如​​​​​​​果​​​​​​​你​​​​​​​选​​​​​​​择​​​​​​​ Skip，你​​​​​​​仍​​​​​​​可​​​​​​​以​​​​​​​试​​​​​​​图​​​​​​​在​​​​​​​救​​​​​​​援​​​​​​​模​​​​​​​式​​​​​​​中​​​​​​​手​​​​​​​工​​​​​​​挂​​​​​​​载​​​​​​​分​​​​​​​区​​​​​​​或​​​​​​​ LVM2 逻​​​​​​​辑​​​​​​​卷​​​​​​​，方​​​​​​​法​​​​​​​是​​​​​​​：创​​​​​​​建​​​​​​​一​​​​​​​个​​​​​​​目​​​​​​​录​​​​​​​，如​​​​​​​, /foo，然​​​​​​​后​​​​​​​键​​​​​​​入​​​​​​​以​​​​​​​下​​​​​​​命​​​​​​​令​​​​​​​：

mount -t ext3 /dev/mapper/VolGroup00-LogVol02 /foo

在​​​​​​​以​​​​​​​上​​​​​​​命​​​​​​​令​​​​​​​中​​​​​​​，/foo 是​​​​​​​你​​​​​​​创​​​​​​​建​​​​​​​的​​​​​​​目​​​​​​​录​​​​​​​， /dev/mapper/VolGroup00-LogVol02 是​​​​​​​你​​​​​​​想​​​​​​​挂​​​​​​​载​​​​​​​的​​​​​​​ LVM2 逻​​​​​​​辑​​​​​​​卷​​​​​​​。​​​​​​​如​​​​​​​果​​​​​​​分​​​​​​​区​​​​​​​的​​​​​​​类​​​​​​​型​​​​​​​是​​​​​​​ ext2，则​​​​​​​把​​​​​​​ ext3 替​​​​​​​换​​​​​​​为​​​​​​​ ext2。​​​​​​​

如​​​​​​​果​​​​​​​你​​​​​​​不​​​​​​​知​​​​​​​道​​​​​​​所​​​​​​​有​​​​​​​物​​​​​​​理​​​​​​​分​​​​​​​区​​​​​​​的​​​​​​​名​​​​​​​字​​​​​​​，你​​​​​​​可​​​​​​​以​​​​​​​使​​​​​​​用​​​​​​​以​​​​​​​下​​​​​​​命​​​​​​​令​​​​​​​来​​​​​​​列​​​​​​​举​​​​​​​它​​​​​​​们​​​​​​​：

fdisk -l

如​​​​​​​果​​​​​​​你​​​​​​​不​​​​​​​知​​​​​​​道​​​​​​​所​​​​​​​有​​​​​​​ LVM2 物​​​​​​​理​​​​​​​卷​​​​​​​、​​​​​​​逻​​​​​​​辑​​​​​​​组​​​​​​​或​​​​​​​是​​​​​​​逻​​​​​​​辑​​​​​​​卷​​​​​​​的​​​​​​​名​​​​​​​称​​​​​​​，使​​​​​​​用​​​​​​​以​​​​​​​下​​​​​​​命​​​​​​​令​​​​​​​来​​​​​​​列​​​​​​​举​​​​​​​它​​​​​​​们​​​​​​​：

pvdisplay

vgdisplay

lvdisplay

在​​​​​​​这​​​​​​​个​​​​​​​提​​​​​​​示​​​​​​​下​​​​​​​，你​​​​​​​可​​​​​​​以​​​​​​​运​​​​​​​行​​​​​​​许​​​​​​​多​​​​​​​有​​​​​​​用​​​​​​​的​​​​​​​命​​​​​​​令​​​​​​​，例​​​​​​​如​​​​​​​：