Why do we need data back up

One of the most important milestones in serious computing is when we realize our data are too valuable to lose them. In general problem is such a finding comes late and data are lost already. At that moment, panic and attempts to recover data are coming, which have a rather uncertain outcome. To avoid inconvenience, it is advisable to start backing up as soon as possible.

What’s back up?

A backup is a copy of data that is separately stored from the original. Beware of a typical error where we just copy the file / directory next to the original and then edit the content. If we edit "backup" content, it is no longer a backup, but a new version of our data. In general, the further the backup (whether physical or logical), the lower the risk of losing data. An example of a well-placed backup can be:

• external hard drive (ideally connected to the computer only for backup time)
  
• online data storage (or cloud storage)
• another computer in a computer network
  

From a physical security perspective, the second disk on the same computer is an inappropriate backup storage. Anyway, some backup is better than none.

What is not a backup

• copy of file/directory we are editing (at best it is "version" of file/directory, but you can read about this in our article about GIT versioning system)
  
• RAID in any form - just think of the case that we delete a file that we have been editing for a long time and had it saved. While in the backup we can find its older version, it is simply deleted on RAID and we can confidently say it is deleted.
  
• a data recovery program - some lost data can be recovered, but many preconditions must be met to make things work. In addition, it depends on the type of damage to the original data, whether their recovery. This approach could be compared to stacking a stack of newspapers that went through a shredder - it's not impossible, but having a copy (backup) of the copier would be more comfortable
  

How to backup

For beginners, it is definitely recommended to use a backup program that may be available in their operating system.

• in Ubuntu e.g. Déjà Dup
• in MAC OS X Time Machine
• in Windows Backup and Restore tool

As a first step on the way to backing up, it's fully sufficient. Typically, the configuration involves checking a box or confirming what prompts, where and how often to back up. For more advanced users who are familiar with the system or are able to write their own scripts, there is a way to back up much more.

What to backup

In short, this could be summarized in two categories:

• User data (documents, photos, videos, ...)
  
• System configuration (configuration files, environment settings)
  

User data is something the user sees or sets himself. In addition to common files and directories, this includes the system settings and programs that it created for itself (= for your user account). System configuration includes settings common to all users on the computer. These include hardware setup, disk encryption, disk mount method, system service, and more.

How often to back up

As often as possible. In practice, this is a compromise between the risk of losing data and the resources required for backups. The specific interval is very individual for everyone. It seems reasonable to back up at least once a week or even a day when working a lot with the computer.