Hard disks are mechanical devices. They are guaranteed to wear out, fail, and lose your data. The only unknown is when they will fail.
Data backup is performed to guard against drive failure. But it’s also done to guard against data loss due to theft, fire, accidental deletion, bad editing, software defects, and unnoticed data corruption.
Before making backups, you must decide:
What data needs to be backed up
How often the data needs to be backed up
How quickly you need to restore the data
How far back in time you need to be able to restore
Based on this information, you can develop a backup strategy, including a backup technology, schedule, and rotation.
Any data that you want to preserve must be backed up; usually, this does not include the operating system or applications, because you can reinstall those.
Table 6-5 lists some common system roles and the directories that should be considered for backup.
Table 6-5. Directories used for critical data storage in various common system roles
|System role||Standard directories||Notes|
|Database server (e.g., MySQL)||/var/lib/mysql||Stop the database server or use snapshots to ensure consistency between tables.|
|Web server||/var/www/etc/httpd/home/*/~public_html||Also include any data directories used by web applications.|
|DNS nameserver||/var/named/etc/named.conf||This information usually changes slowly.|
|Desktop system, or any system accessed by individual users||/home||Exclude cache directories such ...|