Who secure which data in which cycles?
Before data backups begins, responsible person should be identified. This person deal with the question: What data should be backed up? For this it is advisable to get an overview of all directories. The directories with the relevant data are then noted and suitable backup cycles are determined. Should a backup be made after the end of operations or after every data change? And should a backup be done daily, weekly or monthly? Do not worry! Various example and fuse types will shortly provide an orientation.
Once all the data have been classified, the next step is: What are the options for backing up the classified data? - Let's find out:
Which backup types are there?
Complete, differential or incremental! Depending on the type of backup, a backup requires more or less storage space and is slower or faster in terms of data backup or restoration. We bring light into the dark and take a closer look at the three backup types:
What happend with a full backup?
A full backup combines every single file on a system into one backup file. Since the entire file system of a server is backed up, this type of backup takes a lot of time to create. It is therefore important to choose a suitable time for the creation, e.g. close of business or a Sunday.
Suppose you would back up your entire data system (2 TB) every day. In addition, 100 GB of new data are added daily. Then this would mean a high storage load for your chosen storage medium in the long run. Full backups are therefore often used in combination with differential or incremental backups.
A decisive advantage of the full backup, however, shows itself in the restore. If you accidentally lose data on Thursday evening, you can restore all of your data from just a single backup file. This shortens the duration of the restore process so that the affected data can be used again quickly.
|Advantage full backup||Disadvantages full backup|
What does differential backup mean?
A differential backup builds on a full backup. This type of backup is always used when the difference to the last full backup is saved. This means: All data that has been changed or added since the last full backup is summarized in a backup file. Data that has been changed compared to the previous day will be overwritten on the current day:
Imagine doing a full backup every Sunday and a differential backup every Monday through Saturday. Your entire file system takes up 2 TB and the new data that is added daily requires 100 GB. Due to a hardware defect on Wednesday evening, you cannot avoid a restore. To get your current data set again, you have to restore two backup files: 1. the full backup from Sunday (2 TB) and 2. the differential backup from Wednesday, ie: a summary of all changes made on Monday, Tuesday and Wednesday have taken place. (0.3 TB)
|Advantage differential backup||Disadvantages differential backup|
What is an incrementell backup?
An incremental backup only saves the data that has changed since the last backup. In contrast to the differential backup, the changes from the previous day are not carried over to the current day. Because an incremental backup only backs up the data that has changed within a day, this type of backup uses the least amount of storage space.
Let's say you want to do a full backup every Sunday and an incremental backup every Monday through Saturday. Unfortunately, a cyber criminal hacked your filesystem on Saturday morning. To get your data back, you need to restore the entire backup chain. This includes: The full backup from Sunday and each individual incremental backup from Monday, Tuesday, Wednesday, Thursday and Friday. The recovery process is therefore much more complex than the other two types of backup.
|Advantage incremental backup||Disadvantages incremental backup|
The system backup
In addition to the three backup types of file backup, there is also a system backup. This refers not only to a specific file system or database, but to a complete system. A system image of the installed operating system is created, including all system files, installed programs and your own files. You get a snapshot of all drives that are relevant for running the respective operating system. Instead of restoring all files individually, a completely operational system can be restored in the event of a serious software problem. This saves a lot of time compared to a new installation.
Why is 3 times better than twice: The 3-2-1 backup method
The 3-2-1 backup method serves as a first guide for creating a backup strategy. Multiple backup files should be distributed on different data carriers and stored separately from one another:
- Triple copy of important data using a suitable backup type, e.g. full, differential or incremental backup
- Distribute 2 of 3 copies on different storage media, e.g. locally on a backup server, network storage (NAS) or a cloud storage such as the KeyDisc
- Store 1 of 3 copies externally, e.g. online in the cloud of a German certified data center
Should your running server and backup server be affected by elemental damage or theft, the externally stored backup becomes a glimmer of hope. So it is more than just sensible to base your strategy on the 3-2-1 backup method.
Grandfather, father, fon - the multi-generation backup method
Anyone who has already discovered the right backup type for themselves can orientate themselves on the multigenerational backup principle - a popular backup method that can be used to optimize data backup. The aim is to carry out a complete data backup as efficiently as possible. And this is how it should succeed:
At the beginning of a data backup, a full backup is created and then daily backups - the so-called "son backups". The son backups can either be done as differential or incremental backups. At the end of the week, a full backup, the "father backup", is performed. Since this also contains all daily backups of the week, all previous backups (child backups) are deleted. After four weeks, four individual weekly father backups have accumulated, which are then saved by the "grandfather backup".
|Daily backup||Son backup e.g. incremental or differential backup|
|Weekly backup||Father backup replaces son backup with full backup at the end of a week|
|Monthly backup||Grandfather backup replaces father backup with full backup on the one of a month|
TIP: You play it safe if you use different storage media for the various components of the multi-generation principle.
You now have a basic understanding of the different types of backups. For a granite base, we would like to give you specific recommendations from our experts in the next blog post at the end of April. In particular, helpful tips for choosing the right backup technology are summarized so that you can identify the backup method that is right for you.