Saturday, August 2, 2014

What is backup?

Normal backup:

The normal backup is…normal (surprised?). So, what does this mean? It simply means that it copies all the files you have marked to be backed up, and marks the files as having been backed up. You also only need the most recent copy of the backup file (other types of backups requires several files, see below) to restore. This type is usually what you use the first time you backup files.

Incremental backup :

 The incremental backup backs up only those files that have been created or changed since last incremental or normal backup. It also marks the files as having been backed up. A combination of Normal backups and Incremental backups is common, and also a very good combination. It also requires the least amount if storage space and is fast for backing up the data. The disadvantage of this is that it‘s time-consuming to recover files, simply because you need the last normal backup set and all incremental backup sets, which can be stored on several backup drives or tapes.

Differential backup : 

The differential backup is similar to the incremental backup and only copies files that have been created or changed since the last normal or incremental backup. No, it wasn‘t a typo, it doesn‘t check if a differential backup has been run. This is because differential backups does not mark files as having been backed up. A combination of differential backups and normal backups is more time-consuming concerning the backup part then the incremental + normal backups are. But on the other hand it is faster to restore data because all you need is the last normal backup and the last differential backup.

Copy backup :

A copy backup copies all the files you have selected, but does not mark the files as having been backed up. This backup type is useful when you must backup single files between normal and incremental backups because it does not affect these operations.

Daily backup :

The daily backup copies all the files that you have selected that have been modified on the day, without marking the files as having been backed up

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