Lab 9 - Backup and Restore

Table of contents:


Objectives

After completing this lab, you will be able to

- Backup the system

Estimated time to complete this lab: 20 minutes

BACKUP

This lab will explore different simple methods of system backups. The popular "tar" utility will be used. It will be used to perform a differential backup.

Incremental backups are used to back up files that have been modified since the last full or incremental backup. Files that have not changed since the last backup are not backed up again; hence it uses less up less storage space.

Differential backup involves backing up a predetermined list of files since the last full backup, regardless of whether or not they have been modified. The lists usually consist of files that change constantly. This type of backup scheme is not very space efficient.

Tar is an archive utility that is used to create archives i.e. group multiple files together to create a single file.

The syntax for the tar utility is:
tar
Usage: tar OPTION... FILE...

Examples:
tar -cf archive.tar foo bar # Create archive.tar from files foo and bar.
tar -tvf archive.tar # List all files in archive.tar verbosely.
tar -xf archive.tar # Extract all files from archive.tar.

If a long option shows an argument as mandatory, then it is mandatory
for the equivalent short option also. Similarly for optional arguments.

Main operation mode:
-t, --list list the contents of an archive
-x, --extract, --get extract files from an archive
-c, --create create a new archive
-d, --diff, --compare find differences between archive and file system
-r, --append append files to the end of an archive
-u, --update only append files newer than copy in archive
-A, --catenate append tar files to an archive
--concatenate same as -A
--delete delete from the archive (not on mag tapes!)

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