The only way to tackle data loss incidents is by having a solid backup strategy in place. In fairness, most companies today do back up their data rather diligently. Yet, one-third of them experience problems with data restoration. The dichotomy lies in the way a ‘backup strategy’ is perceived.
For the majority, a backup strategy begins and ends with what to backup. For the others, it’s about what to backup and which type of backup to perform.
By understanding the different types of backup, then you can choose the right backup strategy for your business.
Types of data backups
There are three types of backups: full backup, incremental backup and differential backups
1. Full Backup
A full backup is the simplest form of backup. A full backup contains all the data (folders and files in hard drives) that you select/set to be backed up.
Features:
- Least time to restore data.
- Longest time to backup data compared to the other types we shall discuss next.
- Takes up the most storage space. This is why most businesses will complement full backup with differential or incremental backup to reduce the burden on the storage space.
2. Incremental Backup
An incremental backup includes only data that was not backed up the last time.
Features:
- Only needs space to store the changes (increments).
- Can be completed very fast.
3. Differential Backup
Differential backups include only data that was has changed (edited or added) since the most recent full backup. When restoring data from differential backups, you need only restore the initial full backup and the most recent incremental backup.
Simply put, a full backup is done first, and then data (files or folders) that was created or changed since the last full backup are backed up. Simply put
Features:
- Faster data restoration than full backup.
- Requires two components to restore – the initial full backup and the latest differential backup.
- If restoring backups made from incremental backups, you must restore each incremental backup in the order that it was created, beginning with the full backup.
Here’s how a differential backup works:
Day 1 – Schedule a full backup.
Day 2 – Schedule a differential backup. It will cover all the changes that took place between Day 1 and Day 2
Day 3 – Schedule a differential backup. It will make a copy of all the data that has changed from Day 2 (this includes the full backup on Day 1 + differential backup) and Day 3.
Summary of the differences between full, incremental and differential backups
| Full | Differential | Incremental | |
| Storage space required | High | Medium to high | Low |
| Backup speed | Slowest | Fast | Fastest |
| Speed of restoration | Fastest | Fast | Slowest |
| Recovery Media required | Most recent backup only | Most recent full backup & most recent differential backup | Most recent full backup & all incremental backups since full backup |
| Duplication | Stores a lot of duplicate files | Stores duplicate files | No duplicate files |
Another type of backup – often used in disaster recovery strategies is the disk image backup.
Disk Image Backup
An image backup includes everything on the disk (data files as well as operating system – including any hidden or system files). You can use incremental or differential images to supplement your full image backup.
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