Differences between several methods of backup
Hard Drives are not very reliable for storing the data. They are very sophisticated, and can get damaged very easily. Some frequent reasons for corruption of hard drives are failure of hardware card controller or even the spindle mechanism failure. Even failure occurs due to crashing down of read write head and many more. So backup is the procedure used to save the data on the hard drive or any other data storage device.
Mainly backups are of four types: Total, Differential, Incremental and Mirror.
Image 1: Types of Backups
1. Total Backup
This backup is also known as normal backup. In this backup every file which we have selected is backed up and this is done regardless of what status the archive bit is having. When the process is completed the software used for backup off’s the archive bit status for each and every backed up file. If we have been provided by different choices for backup always prefer full backup because all the files which are backed up remains in the same tape which makes it easier for retrieving them. Also the backed up data is stored on each tape so if one tape fails, data can be retrieved from other tape.
In this option, User can clear the archive bit and there is no need to set any options.
After completing your Backup Wizard you can select advanced option tab and select the Backup types. Refer the below image.
Image 2: Select your backup type
2. Differential Backup
Differential backup is also known as partial back. This backup copies the file which is selected to the tape only when the bit of archive is on; this indicates that the bit has changed since the last time when full backup was taken. This backup keeps the bit of archive unchanged for the copied files. In this backup, the data is stored on only two tapes; one contains the last full backup data and other with differential backup data.
3. Incremental Backup
Incremental is same as that of partial backup and functions same as that of differential backup only the difference is the bit of archive is cleared. So this backup contains only the files which are changed since the previous full backup or the incremental backup. If this backup is used by you everyday then files changed on Thursday remains on Thursday tape, Friday on Friday tape and so on. When this backup is used, complete set contains tape of last full backup and the each and every backup taken since the previous normal backup. Only advantage of this backups are they require less time for taking the backup and many versions of backup are kept for the files changing frequently. Disadvantage is the backed up files spread all over the tapes making it difficult to locate particular file.
4. Mirror Backup
This backup synchronized the data to other set of hard drive which are removable. User can use this type of the backup to protect the offsite data. This backup operation creates the duplicate copy of the entire data and hard drive content to the other places.
This shows the differences between different types of Backup procedures. Users can select the procedures as per their requirement, however total backup is always recommended.