Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Programming
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Databases
Mail Systems
openSolaris
Eclipse Documentation
Techotopia.com
Virtuatopia.com
Answertopia.com

How To Guides
Virtualization
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Windows
Problem Solutions
Privacy Policy

  




 

 

12.3. Selecting the backup tool

There are many tools that can be used to make backups. The traditional UNIX tools used for backups are tar, cpio, and dump. In addition, there are large number of third party packages (both freeware and commercial) that can be used. The choice of backup medium can affect the choice of tool.

tar and cpio are similar, and mostly equivalent from a backup point of view. Both are capable of storing files on tapes, and retrieving files from them. Both are capable of using almost any media, since the kernel device drivers take care of the low level device handling and the devices all tend to look alike to user level programs. Some UNIX versions of tar and cpio may have problems with unusual files (symbolic links, device files, files with very long pathnames, and so on), but the Linux versions should handle all files correctly.

dump is different in that it reads the filesystem directly and not via the filesystem. It is also written specifically for backups; tar and cpio are really for archiving files, although they work for backups as well.

Reading the filesystem directly has some advantages. It makes it possible to back files up without affecting their time stamps; for tar and cpio, you would have to mount the filesystem read-only first. Directly reading the filesystem is also more effective, if everything needs to be backed up, since it can be done with much less disk head movement. The major disadvantage is that it makes the backup program specific to one filesystem type; the Linux dump program understands the ext2 filesystem only.

dump also directly supports backup levels (which we'll be discussing below); with tar and cpio this has to be implemented with other tools.

A comparison of the third party backup tools is beyond the scope of this book. The Linux Software Map lists many of the freeware ones.

 
 
  Published under the terms of the GNU General Public License Design by Interspire