The most important task of any system administrator is backing up the systems they are responsible for.
Not putting the system up or not keeping it running as not backing it up and being able to restore is primary.
A system with no backup cannot be relied upon for any real purpose, because if anything goes wrong your data is gone, and that’s really bad news.
Something always goes wrong eventually, no matters how much you try to avoid it, and without good backups all of your work, and possible your entire business is just plain gone.
A good backup strategy is composed of backup, storage, verification, and restoration.
The backup component covers selection of method and which data to backup (all of it by choice).
Storage covers both what media you back up onto as well as where you keep them (if your building burns down, tapes kept in the server room will be useless).
Verification is a crucial component of a backup strategy, you have to know you have usable data.
Lastly, you need to be able to get the data back to where it can be used.
There are two main strategies for backups: Disaster Recovery and Archival.
DR backups are designed to restore a system to a working state.
To do this you backup the entire system so that you can restore it onto another machine to get a working system.
An archival strategy is concerned with retrieving historical data (‘give me the customer database as it appeared at the end of last year’) and not with restoring a working system.
Both strategies can, and probably should, be combined.
An archival-only strategy requires the system administrators to reinstall and reconfigure the operating system prior to restoring the data; this takes longer and is more error prone.
Any backup strategy must be tested.
A DR backup is tested by restoring a system backup onto a fresh system to make sure you can recover from an emergency.
Archival strategies are tested by retrieving files and verifying that you can find the files you need and that they are readable once restored.
An untested backup strategy is usually a complete waste of time and money.
For web hosting clients, you will usually do your backups with the cPanel administrative interface.
cPanel will let you backup your entire hosted site, your databases, or your home directory (‘which will contain your website but not the data behind it’).
To perform a backup you simply access the Backup control panel and select a type of backup.
The system performs the backup and downloads the file to your local system.
These backups can be restored through the same interface.
To test, you would create a new hosted site and restore your backups to it.
The downloaded backup files are important (possibly confidential) data and should be integrated into your local backup strategy.
At the least, burn them to disks if you can’t arrange to include them in your main backups.
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