Differential Backup Technology

One of popular data backup types is differential backup. It implies backup copying of all files that have been changed since the last complete backup was performed. It is widely used alongside with incremental and full data backup, helping to keep the backup storage in the most up-to-date mode. If something happens to a system, it can be recovered maximally close to the moment of crash, if the backup agent is scheduled to a constant mode.

The differential backup mode is a midpoint between the full and incremental types. It is slower than the latter, but much quicker than the full type. It needs bigger memory storage than the incremental one, and respectively less space than the full backup. It is also known as the block level backup technology. Being less in size, it needs more time to be restored in comparison with full backup, but less time than an incremental backup copy usually needs.

Most of differential backup software can perform full backup, while only few of them offer incremental backup. The reason is that incremental copying is not needed for full system restoration, it is enough to have a full and differential backup copy. Usually block level backup software is adjusted to backup data in two modes. A full backup is performed once a week or once a month, while the block level backup is performed daily. In such a mode it is very easy to restore a system. For instance, if the last full backup was made on Friday, and some system failure took place on Tuesday, you just need to restore Sunday's full backup and Monday's differential one.

In this sense differential backup software is more convenient than incremental backup software. If the same situation happens to a system with an incremental backup kit, you will need to restore Friday's full backup, and Saturday's, Sunday's and Monday's incremental backups. It takes more time for full system restoration.