Red Hat Enterprise Linux 5 Administration Unleashed

Using Amanda for Backups 223. Do multiple administrators have the knowledge to recover each system in case ofpersonnel changes or vacation times?. Are the processes well-documented so they can be easily accessed and reviewed on aregular basis?Incremental versus Full BackupsIf your organization is large or modifies the same subset of data frequently, you mightwant to consider incremental backups. You start off with a full backup and then only backup the data that has changed since the last backup. This often saves disk space on thebackup servers and shortens the time it takes to perform backups.Even if you implement incremental backups, it is a good idea to perform a full backupless frequently (for example, every one or two months if the incremental backups areperformed weekly). Each time you perform a full backup, the subsequent incrementalbackups are based on the last full backup. When you do have to recover the system, therestoration process begins with the last full backup and then all the incremental backupsare applied. The time it takes to recover will depend on how many incremental backupsyou must apply.Using Amanda for BackupsRed Hat Enterprise Linux includes AMANDA, or the Advanced Maryland AutomaticNetwork Disk Archiver, for assisting in backups. AMANDA works by setting up a masterbackup server on the network and backing up systems running different versions of UNIX(using tar or dump) and Microsoft Windows (using SAMBA) to tape or hard disk. Thissection covers setting up the server and clients on Red Hat Enterprise Linux. Refer towww.amanda.org for setup instructions for other operating systems.NOTEExtensive documentation is available on www.amanda.org. This section providesenough information to get you started. Refer to the website for more details.CAUTIONThe tar and dump utilities do not preserve access control lists (ACLs) associated withfiles. Refer to Chapter 7, “Managing Storage” for details on ACLs.10Setting up the Amanda ServerBackups done by Amanda are done in parallel to holding discs on the hard drives, andthe data is then written to the tape or backup media. Software or hardware compressioncan be used, with hardware compression using fewer CPU resources.