Full Backup

The term Full Backup refers to the entire copy of a filesystem to another storage media, which means that every single file and folder gets copied over. This is exactly how backups used to be, some years ago there weren’t any options so if you wanted to back up your computer, you had to create a full copy of it’s contents.

Full backups can be performed in basically two ways

The first one is the “ordered filesystem backup” which means that the entire filesystem is copied over keeping file definitions, thus making the data in the back up “human” readable (well, at least readable to a computer without any additional software). The second one is the “image backup” which means that there’s a single file or “image file” created that has the contents of every single file or folder but that in order to preserve space, changes the data order and sometimes applies some compression to it. Image files are usually readable by the same software that created them, but it’s impossible to access files in the backup directly.

One of the drawbacks of full backups is that they take a lot of time to be created, as most computers hold over 50 Gb of data, and they also require large storage devices. Let’s say that you want to back up your 80 Gb drive to DVDs. A regular single layer DVD holds 4.7 Gb of information, therefore you would need at least 18 DVDs and it would take over 2 hours to create the backup.

The second drawback is that it’s impossible to keep an updated full backup without creating a complete new backup set. So if you manage 5 computers and you want a full weekly backup, you would spend over 10 hours a week to keep those backups “current” (with a 7 day old range).

However there’s a huge advantage of full backups, and that is that a full system can be restored easily, as you just have to copy the full backup to the original drive.

Nowadays full backups are usually performed to restore computers to their “initial state” as it takes less time to restore a full backup than to install the operating system, set up the proper drivers, install updates and install additional software. They are also created to have “cloned” systems to be executed in virtualized environments.

To keep a full backup of a regular computer or server, the best media is to have a spare hard drive, as it will hold more information than DVDs or USB devices.