Data backup consists in saving a copy of data to another data carrier that is preferably located in a different place than the backed up device (computer, disk, phone, tablet, server). This copy is called a backup or backup copy, and allows for data recovery if something happens to the original. Backup uses specialized software.
Backup or backup copy should ideally be physically stored in a location other than the original. Why? It is a good idea to ensure that not both the original and the copy will be lost in case of a larger accident, say fire or flood. In other words, such an event must not affect all the places where the data is stored. What would be the backup good for if it burned together with the original? This is the reason why Cloud Backup has gained a lot of popularity in recent years - the data is encrypted and stored securely in a completely different location than your computer and your office. If, for some reason, you don’t want or cannot use cloud backup, it is important to at least make sure that the backup and the original are as far away from each other as possible (even if it were at two different locations within a single building).
Backup data proves itself useful in case of damage or loss of the original data as well as on some other occasions such as audit. Quickly available backups are called hot backups. Backups intended for archival purposes are called cold backups and they are not expected to ever be used.
Backups can be made either on the irregular (ad hoc) basis, regular basis (following a precise schedule, e.g. every hour, every day, every month, etc.) or continuously.
What is so important about backups?
Nobody wants to lose their data, nonetheless, such event can occur quicker than you might think. This can be due to one’s own mistake, somebody else’s efforts or due to the technology failure. You may accidentally delete some files, drop your phone, forget your password, your laptop might get stolen, attacked or hacked, your hard drive or other repository may stop working and so on. However, information and data stored in digital form have one big advantage - they are relatively simple to back up and thus avoid the above-mentioned situations. When your data is backed up, a number of unpleasant situations can be avoided.
What should be backed up?
Let stress the fact that to back up your data and to back up the whole system are two distinct things.
Data backup concerns only data content (documents, files, photos, etc.), which is mostly the most valuable for us. Backups of content (data) may not only concern personal computers and portable devices, but also, for example, the servers, as they may also be burned, attacked, or inadvertently deleted.
Backup of the whole system, on the other hand, includes all your data and all your settings as well. This is more demanding than just a simple data backup but it allows you to completely recover the data AND custom settings (the original behavior) of your computer or cell phone. In the past, the custom settings migration was a problematic task, today, most operating systems can handle it - not only for enabling backups, but also to facilitate switching between multiple devices belonging to one user. For example, using backups of custom settings, Apple ensures a smooth transition of their users from one iOS device to another, so does Android, Windows contains this function only partially. System backup can, among other things, restore or migrate your email settings, your bookmarks, saved browser passwords, installed applications, favorite apps, and so on.
Where to back up? What are the options?
- Backup of data to some portable media - typically using external hard drives or flash drives connected via USB port. This is relatively easy but the disadvantage is that you need to connect the backup media every time you want to back up
- Backup of data to a backup server - typically to Network Attached Storage (NAS) or other servers. This backup can take place remotely, in the background and is usually automatic. Therefore, data can be backed up continuously or at any time that you are connected to the network.
- Backup of data to the cloud - to remote cloud servers. Similar to the previous type of backup, except that the backup is stored in the cloud.
What happens when my data is lost? What about data recovery?
Again, it depends on the type of data and the method used to do the backup. If you only back up data, you can only restore your data without custom settings.
If you use backup software, it will automatically give your the possibility of your data recovery. In most cases, you only need to restore the last known (or last saved) version. However, sometimes we need to recover a much older version. Imagine, for example, that a colleague has accidentally deleted some files, but you would only find out after a month. In such a situation, you have to be able to restore the version that still contains the deleted data but, at the same time, not to overwrite or lose anything that is newer than that. Such a situation is much more demanding than just a simple restore of the latest version.
The duration of data recovery - the recovery time - is the key here, that is, how quickly you are able get back to normal. For personal devices, it can be tens of minutes or hours, but the recovery of servers must be a number of times quicker. The shorter the recovery time, the more the backup system is financially demanding. For example, servers requiring high availability - that is, operation with no failures - are able to switch to a backup immediately without the user noticing anything at all. The cost of building and maintaining such infrastructure is, however, high because the backup server must be kept in the same state as the the main one at all times. In a nutshell, everything is built twice.