If you were to ask a person that was not familiar with computer backups, most would think that a backup was just an identical copy of all the data on the computer. In other words, if a backup was created Tuesday evening, and nothing changed on the computer all day Wednesday, the backup created Wednesday evening would be identical to the one created on Tuesday.
While it is possible to configure backups in this way, it is likely that you would not. To understand more about this, we must first understand the different types of backups that can be created. They are:
- Normal (Full) Backups
- Incremental Backups
- Differential Backups
- Mirror Backups
Full backup is the starting point for all other backups. It contains all the data in the folders and files that are selected to be backed up. Because full backup stores all files and folders, frequent full backups result in faster and simpler restore operations. Remember that when you choose other backup types, restore jobs may take longer.
This approach is good when the project includes not so large amounts of data.
An incremental backup stores all files that have changed since the last backup. The advantage of an incremental backup is that it takes the least time to complete. However, during a restore operation, each incremental backup must be processed, which could result in a lengthy restore job.
This approach is good when the project includes too many files to back up them all each time. It is fast and takes less time for incremental backups. Incremental backups take less disk space. It allows you to create backups frequently. However, to restore all the files, you have to restore the last full backup, and all the following incremental backups.
A differential backup contains all files that have changed since the previous full backup. The advantage of a differential backup is that it shortens restore time compared to an incremental backup. However, if you perform the differential backup too many times, the size of the differential backup might grow to be larger than the baseline full backup.
Differential backup is intermediate between the first two approaches. It is also good when the conditions are intermediate.
Each differential backup includes all the project files changed since the last full backup. It takes less time and space than “Always Full”, but more than “Full+Incremental”. The good thing is that restoring is simpler than for (2) – you’ll have to restore the last full backup and the last differential backup.
Mirror backup includes all files that have changed since the last normal (full) or mirror backup, missing files also get deleted from the backup set. The resulting backup archive consists of either one compressed file or one folder.
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