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To access the contents, click the chapter and section titles.
Complete Idiot's Guide to Linux
The dump CommandThe dump utility is not installed by default on your system, but it is included on your CD. In the col/install/rpms directory, it should be named something like dump-x.i386.rpm, where x will be some numbers related to the version of the program. To install the program, visit the col/install/rpms directory on the CD. As root, issue the following command: rpm -i dump*.rpm The dump command uses the following syntax: /usr/etc/dump [options[argument ...] filesystem] The dump command tracks the scope of a backup by assigning each backup a level. Levels range from 0 to 9. Level 0 copies the entire file system. Subsequent dump levels copy only files that have changed since the most recent dump with a lower-level number. The typical strategy is to begin with a level 0 dump and then make incremental backups at regular intervals. Level 0 dumps should be performed with extreme care; they should be run with the machine in single-user mode, and fsck (the file system consistency checker) should run before the dump to verify that the file system is consistent. This is important, because most of the files you restore will come from dump level 0 tapes if you dont plan to substitute your CD for a level 0 backup! For more information, see the fsck and dump man pages. One disadvantage worth noting is that dump is unable to back up single directories or files; it can only be used to back up an entire file system. To back up individual files or directories, use tar or cpio. For information on how to use these programs, refer to your Linux documentation.
Note that tapes created under one hardware/software configuration are not usually portable to other operating systems or drives. In some environments, even tapes created with older versions of the dump program are unreadable by newer versions of the restore program. So test your backups when you do an upgrade, and keep old versions of the program close by. Tape Capacity The one issue with dump is that it doesnt calculate how much data your tape can hold for you. Therefore, youll need to figure capacity by yourself in order to make correct use of your tape. This might seem easy enoughbut it isnt. Each tape system has a different density (the amount of data that can be written to one inch of tape). Tapes are of different lengths, and dump calculates all these settings based on a nine-track tape running at 1600 bytes/inch and with a default tape length of 2300 feet. Sound confusing? Dont give up. The basic math for calculating your tape drives capacity is as follows:
Heres an example for a 90m 1.95GB DDS tape:
Whew! In a world where tape density could be figured out automatically by querying the device, it seems silly to have to do this. But heck, this program was originally done eons ago, and given the different types of tape devices (SCSI or otherwise), that could be a challenging task to develop, too! Also, remember to check your manufacturers Web site. It is possible that it posts information on how to use its hardware with dump. Whatever you do, remember to write this number down and stick it in a note to the bottom of your drive. That way you wont have to figure it out again. If you dont have a calculator handy, remember that KDE has one that should work just fine.
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