How does differential backup preserve your data?
Adopt the best data backup procedures, with different options open to you: automatic backup, outsourced backup, incremental, differential... How do you choose? To make the right choice, it's important to understand what's at stake with each method, and in particular how differential versus incremental backup works.
Differential backup - definition
What is differential backup?
Differential backup consists in restoring the last full backup to date, and then all the differences noted on files modified since then.
It is :
- quick to restore,
- voluminous in terms of storage,
- more or less time-consuming to deploy.
How do backups work?
Differential backup
To understand its characteristics, let's take a closer look at how it works. Differential backup, as its name suggests, takes differences into account.
Starting from a reference backup, it re-lists all modifications each time.
Incremental backup
To understand what the differential method involves, and what characterizes it, let's compare it with its counterpart: the incremental backup. Incremental backup also starts from a reference version, but only lists changes once, and superimposes progressive backup layers.
What are the pros and cons?
On the restoration side
The differential method offers a clear advantage on the day of restoration. Since the latest version has recorded all the differences with the original version, all you have to do is restore one and restore the other to obtain the total.
Incremental backups, on the other hand, have broken down all modifications into progressive backups. So, to recover them all, you need to restore all these versions. This can be a much more time-consuming operation.
The day-to-day side
While it's quick to restore, the differential method takes longer. This is because new elements have to be saved each time, even if they have already been saved with previous backups. It doesn't capitalize on previous versions, and therefore has a greater volume of data to process each time.
The incremental method, on the other hand, has the advantage of being easier to implement. Each version incorporates only new modifications made since the previous incremental version. As a result, data volume is reduced to a minimum. This means faster backup.
Practicalities
Being able to restore a backup quickly is a good thing. However, there are times when you want to reach an intermediate backup state: neither the one you started with, nor the one you ended with. We'd like to find a version somewhere in between.
Coming back to this point, the differential method offers no solution. Unless, as some IT departments do, you set up several backups, at different dates and on separate tapes.
With an incremental backup, it is possible to return to a point in time T, since the different versions have been kept continuously. The method thus offers a solution known as remanence. This can be of real benefit in certain situations.
When should a differential backup be deployed?
Depending on your data volume
The choice of a backup method depends not so much on the size of your company, as on the volume of data you process.
Your organization may be relatively small, juggling Big Data. On the other hand, a large company may not have a great deal of data to back up on a daily basis.
IS consequences
If your data reaches a large volume, the choice of a differential method may not be optimal.
The energy and disk space required for each backup will be considerable, taking up memory and mobilizing your IS (Information System).
The progressive option
If, on the other hand, the volume of your modifications over time takes up a relatively reasonable amount of memory space, the differential method may prove interesting.
Or, in the case of really small data sets, the possibility of making a full backup each time may even be considered.
How do you set up your backups?
In situ or off-site, in-house or outsourced
Whichever backup you choose, you have two options for implementing it:
- launch it manually at regular intervals,
- program it to run automatically at a given frequency.
Backups can be stored :
- either locally, on your company servers,
- or in the cloud, on mysql databases on outsourced servers.
How can backup software help you?
Numerous backup software packages are available, including NeoBe, oodrive_save, Cobian backup and Beemo2cloud. In SaaS (Software as a Service) mode, you can remotely orchestrate your backups online.
Media are synchronized in real time. You can back up information from your company computers, as well as from business-related tablets and smartphones.
The importance of securing your data
Backup solution providers offer security guarantees for data protection.
So you can store your sensitive information, or that of your customers, and seal access to it under an encrypted device, such as Rsync.
All your documents, business software and work tools can thus be archived, and remain available for consultation on demand and according to an access rights management protocol.
Data backup is all the more important these days, given the frequency of data theft and loss. Depending on your data volume and operating requirements, differential backup may be an interesting option. Various software solutions offer outsourced data management.
Article translated from French