Types of backup

Types of backup

Copy backup
A copy backup copies all the files you select, but does not mark each file as having been backed up (in other words, the archive attribute is not cleared). Copying is useful if you want to back up files between normal and incremental backups because copying does not affect these other backup operations.

Daily backup
A daily backup copies all the files that you select that have been modified on the day the daily backup is performed. The backed-up files are not marked as having been backed up (in other words, the archive attribute is not cleared).


Normal backup
A normal backup copies all the files you select and marks each file as having been backed up (in other words, the archive attribute is cleared). With normal backups, you only need the most recent copy of the backup file or tape to restore all of the files. You usually perform a normal backup the first time you create a backup set.

http://technet.microsoft.com/en-us/library/cc784306(v=ws.10).aspx

• Differential backup   

A differential backup is a type of data backup that preserves data, saving only the difference in the data since the last full backup
A differential backup is a cumulative backup of all changes made since the last full backup, i.e., the differences since the last full backup.
The advantage to this is the quicker recovery time, requiring only a full backup and the last differential backup to restore the entire data repository.
The disadvantage is that for each day elapsed since the last full backup, more data needs to be backed up, especially if a significant proportion of the data has changed, thus increasing backup time as compared to the incremental backup method.

http://en.wikipedia.org/wiki/Differential_backup

• Incremental backup

An incremental backup is one that provides a backup of files that have changed or are new since the last incremental backup
it is one that backs up only the data that changed since the last backup — be it a full or incremental backup
The most basic form of incremental backup consists of identifying, recording and, thus, preserving only those files that have changed since the last backup. Since changes are typically low, incremental backups are much smaller and quicker than full backups. For instance, following a full backup on Friday, a Monday backup will contain only those files that changed since Friday. A Tuesday backup contains only those files that changed since Monday, and so on. A full restoration of data will naturally be slower, since all increments must be restored
http://en.wikipedia.org/wiki/Incremental_backup

• An Incremental backup backs up only the selected files that have their archive bit set to ON, setting them back to OFF.

a backup of all files that are new or changed since the last backup whether it was a full or an incremental.
The advantage of an Incremental is that it takes the least amount of time and media of all the backup methods.
In the case of restoring with Incremental backups, all the Incremental backups since the last full backup plus the last full backup would be necessary.




A Differential backup backs up only the selected files that have their archive bit set to ON but does not set the archive bit back to OFF.
A Differential backup will back up all selected files that are new and changed since the last full backup.
at restore time; you'll need only the last full backup and the last differential to get a complete restore

Reference:
http://wiki.answers.com/Q/What_is_the_difference_between_an_incremental_backup_and_a_differential_backup

• The Bacula® Open Source Network Backup Solution

Bacula is a set of Open Source, computer programs that permit you (or the system administrator) to manage backup, recovery, and verification of computer data across a network of computers of different kinds
http://blog.bacula.org/

Bacula is an open source network backup solution that allows you create backups and perform data recovery of your computer systems.

it follows the server-client backup model;
we will focus more on the backup server and the backup clients than the individual Bacula components.

A Bacula server, which we will also refer to as the "backup server", has these components:
    Bacula Director (DIR): Software that controls the backup and restore operations that are performed by the File and Storage daemons
    Storage Daemon (SD): Software that performs reads and writes on the storage devices used for backups
    Catalog: Services that maintain a database of files that are backed up.  The database is stored in an SQL database such as MySQL or PostgreSQL
    Bacula Console: A command-line interface that allows the backup administrator to interact with, and control, Bacula Director
Note: The Bacula server components don't need to run on the same server, but they all work together to provide the backup server functionality.

A Bacula client, i.e. a server that will be backed up, runs the File Daemon (FD) component.
Daemon is software that provides the Bacula server (the Director, specifically) access to the data that will be backed up.

By default, Bacula is set to use the PostgreSQL library.
https://www.digitalocean.com/community/tutorials/how-to-install-bacula-server-on-centos-7

• Amanda Community Edition

Amanda Community Edition is a free and stable version of the world's most popular open source backup and recovery software Amanda. The Amanda project started at the University of Maryland in 1991. Over the years hundreds of developers contributed to the project
https://www.zmanda.com/amanda-community-edition.html