Image based backup is a method for a virtual machine (VM) or computer to create a duplicate of an operating system (OS) and all the information connected with it, plus the system state and any operation configurations. This backup is now saved as a one file that is labeled as an image.
The benefit to an image based backup is simple because all the data is collected in one pass, giving you updated bare metal restore (BMR) ability from each file-based backup.
Image Based Backup
Image-based backups can perform a backup online, perform some different hardware restores, and allow file level restores from the image backups. This process can also recover any server remotely across a wide area network (WAN) or a local area network (LAN) and allow the backup images to be saved to an assortment of dissimilar media. Most products will also support encryption.
Since image level backup applications use what is called a snapshot, all of the information, including any deleted files and any empty disk blocks, are also backed up. To help cut down on the amount of data to be stored, some dealers are including data reduction technologies like data deduplication.
Since an image-based system looks primarily at the arrangement of data that is on the disk, any change that will shift the position of data within a file can alter a huge part of the file on the disk
and require the backup system to retransmit most of the file.
Image Based Backup and Files
An image-based system will also look at the actual file system. It will view defragmented files as block changes and that it must retransmit the pieces of the files that have changed position.
Also, an image-based system can view the drive as a whole unit; it will not recognize that certain individual files are already present on the storage device, so any changes to the image including those generated by common files must be transmitted for each backup.
Image-based systems have to mount or scan the full disks images to find files and to make them available for individual restores. This process is typically time consuming and, if poorly automated, may display these files in awkward interfaces.
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