Incremental Backup Software
Incremental backup is a process of backing up software by only backing up the delta. This means only backing up the changes since the last backup. The very first backup would effectively back everything up, but post this only the changes would be backed up. The advantage of this process is that the incremental backups will tend to be of a much smaller size than if a full backup is done every time. Also the backup process itself should last less time. The disadvantage is that an incremental backup relies on each backup being uncorrupted, so if even one backup is corrupted then a data loss will occur. Incremental backup is usually accompanied by a periodic full backup, to minimize the data loss in case that one of the incremental backups is corrupt. A simple example to illustrate how an incremental backup works. A word document contains 'Hello world' and is backed up, then an edit is made to Change it to 'Hello world automatic backup', only automatic backup part would be stored in the incremental backup. The incremental backup gets its name because it does an increment every time it backs up rather than the full backup.
Usually incremental backup is included in most backup strategies for example windows vista backup does it this way, as doing constant full backups can start to take up a huge amount of space. Consider a strategy where videos are wanted to be backed up. By using only full backups very large files would be constantly being backed up when they are probably never going to change from their original form. This would waste a huge amount of space. Given that a few videos can quickly fill up one dvd it will start to make the cost prohibitive.
Advantages of an incremental backup
- Storage space requirements are the smallest
- The backup process takes the least amount of time
Disadvantages of an incremental backup
- If a previous backup file is corrupted then all the files associated with the corruption from then onwards will be corrupt.
- The restoration process takes the longest time
Improvements which some software vendors do to mitigate the disadvantages
- Merging of backup files. This will decrease the time it takes to do a restoration
- Providing a mixed strategy of doing full backups and incremental backups, that way the loss of files is minimized in the case where and incremental backup file fails.