In this article, I want to describe a little the concepts of redundancy and backup with a classic example of data loss that more or less could start like this:
Hi, I had all the photos of my honeymoon on this USB stick but I had been having problems for a while and now I can't open anything anymore, would you take a look?
Yes, you got it right, the most important photos of your life, honeymoon or your children (but the same goes for invoices, emails, and documents of various kinds) that could be lost forever. Are we sure there isn't a way to avoid this situation? Of course, there is and the answer is surprisingly simple: BACKUP.
Redundancy
In the IT field, but the term can also be found in other areas, redundancy has this meaning:
Duplication of critical components or functions of a system with the intention of increasing reliability of the system, usually in the form of a backup or fail-safe, or to improve actual system performance [...]
This duplication of critical components in the IT environment can be done mainly in two ways to which I give a brief mention:
Mirror: it is used to indicate an exact copy of a set of data in which multiple copies of the same content can be found on different computers/servers so that the same resource can be made available to a greater number of users without overloading of a single computer/server. This is the case of CDN, where resources are distributed on several geographically distributed servers and depending on the user requesting them, the resource is served by the "closest" server;
Raid: acronym for Redundant Array of Independent Disks is a particular type of connection of multiple disks that are used as if they were a single storage volume. This aggregation according to the "way" in which it is done allows to increase performance, increase storage capacity, and in most cases improve fault tolerance.
Backup
So here we are at the answer to the question
Are we sure there is no way to avoid this situation? Yes of course: the BACKUP!
To limit as much as possible the probability of losing all the photos of your honeymoon, children, invoices, etc..., periodic backups of our information must be made, possibly in a redundant way, so in different and independent storage devices so that the likelihood of our data being lost forever is minimized precisely because our data is saved from multiple places.
Saving your most important data on as many of these devices minimizes the likelihood that at some point your honeymoon photos will be lost forever.
The 3-2-1 Rule
A simple rule to remember is the 3-2-1 rules which more or less can be said in this way
You must have at least 3 copies of your important data, in at least 2 independent devices and at least 1 of them must be offline
Bye, Alberto
