Rescuing Linux Systems--Generic and Distribution-Specific Safety Nets - page 8
Sending Out an SOS
Kent Robotti provides two excellent rescue systems from his Web page at http://www.tux.org/pub/people/kent-robotti/looplinux/rip/index.html. This page provides floppy and CD-based versions of the RIP rescue system, and a similar floppy-based rescue system known as RamFloppy. All of these systems are designed to help you boot, repair, back up, and otherwise rescue existing systems.
All of these rescue disks take a similar approach to Tom's Root Boot by using a combination of CRUNCHbox and BusyBox to maximize the number of utilities that it can provide by minimizing the disk space that they require. CRUNCHbox is a mechanism whereby multiple static executables are combined into a single utility that executes the specified utility based on the name by which it is invoked. The utilities that are crunched together on the RamFloppy rescue disk include BusyBox, providing double savings in some sense.
The RamFloppy and RIP floppy rescue systems support ext2, ext3, is9660, ntfs, umsdos, ReiserFS, and VFAT filesystems, making it easy for you to mount and access these types of filesystems on the computer that you are rescuing. They provide the e2fsck command to enable you to correct filesystem corruption on ext2 and ext3 filesystems, includes the tune2fs command for repairing ext2 and ext3 filesystem attributes, and includes the badblocks utility to search for and identify bad blocks on an existing disk. It also includes tools for creating ext2, ext3, and ReiserFS filesystems. For truly damaged disks, it includes fdisk for basic partitioning and mke2fs and mkreiserfs for creating new ext2, ext3, and ReiserFS filesystems.
The RIP bootable rescue CD provides all of the tools on the floppy systems, but adds support for the JFS and XFS journaling filesystems, as well as the fsck.jfs and xfs_repair utilities that can be used to repair corrupted filesystems of those types. The RIP CD includes easier-to-use filesystem partitioning utilities such as cfdisk and sfdisk, in addition to fdisk.
The RIP CD also includes utilities such as mkisofs and cdrcord that enable you to back up data from a damaged system onto CD. Beyond simply backing up files, the RIP rescue CD also include the partimage utility that enables you to create image files of some or all of your existing partitions, which you can then also back up onto CD (dependent on their size, of course). This can save an incredible amount of time if you find that the easiest way to repair your damaged system is simply to reinstall it, but want a quick and easy way to recreate some of your existing filesystems. The image files produced by the partimage utility only contain portions of the filesystem that actually held data, making them potentially much smaller than the partitions that originally held the filesystems.
All of the RIP and RAMFloppy rescue systems can be used to boot an existing Linux system by passing the "linux root=/dev/whatever" boot options to the boot loader. You can use other command-line options to boot into single-user mode or to specify an alternate to the standard "init" program. This last option enables you to boot directly into a utility such as /bin/sh if the init program or related startup scripts are damaged on the system that you are rescuing but you still want to boot from the hard disk's root partition.
The RIP rescue CD and floppy, and the RamFloppy rescue floppy are free, powerful rescue disks that include support for an impressive number of filesystems, devices, and backup mechanisms. They do not provide network support unless you use them to boot from an undamaged root partition whose kernel and modules provide network support (and which provides network-related utilities). However, their focus on enabling you to repair filesystems of various types and create backups of existing data can be a tremendous asset when your only other alternative is to lose data or slowly copy smaller files to small external media such as floppy disks.
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