UBQ ID Number: UBQ000024
Last Modified: 2000-06-01 at 10:43:09
SUMMARY:
Explanation of an Image (Disaster Recovery) backup as opposed to a standard file-by-file backup
DETAILS:
What is an image backup? An Image backup bypasses the OS file system and reads the physical sectors of a disk sequentially until all of its sectors have been backed up (unless using UltraBac 6.3 or above; see note below). An image backup can inadvertently perform a "dirty" backup of an open file or related set of files that are in a state of modification – there is no OS file integrity guarantee. This means that applications such as SQL, Exchange and other programs that could be modifying data on the disk should be closed prior to backup. The Image set can perform any required "before" and/or "after" batch command to shut down and start up an application or service, with minimal down time.
An image set automatically defines the entire disk drive. During a backup or a restore, individual partitions cannot be included or excluded, though UltraBac offers a "file-by-file restore of an image backup" which can include or exclude files and/or directories. The benefit of an image backup is that every partition on a disk is 100% backed up including boot records and the file systems contained on the physical disk. A disk that has been backed up as an image may be restored as an image or it may be mounted as a virtual drive and then restored file by file. BEI's image backup has been designed to work alongside file-by-file backup – not replace it.
An image backup set can be included as an additional set in a scheduled backup group. Always make the image sets the first sets within the group and the media should be cleared. If the backup might span two or more media, this ensures the image backup will start at the beginning of the media. Currently the image set must not span media. The image set being the first set also greatly improves access time when locating an image set stored on tape during disaster recovery.
Performing an image backup or restore is essentially a matter of copying the image from the source device to the target device. An image backup can be accomplished either by performing an "Integrated Image" backup or by performing an "Stand Alone" backup or recovery, the process is basically the same for all. A Stand Alone Backup boots using Stand Alone floppies, and produces an "Ultra Clean" copy but can not be scheduled. An Integrated Image backup can be scheduled but must shut down programs that could cause a dirty backup as described above.
Note: UltraBac 6.3 and above provides the user with image options. Selecting the "Enable in-use cluster backup for partitions with known file-systems" option forces UltraBac to image only those disk clusters which contain data. The "Always Backup Partitions Individually" option applies to images of hard drives where unallocated free space exists. With the "Always Backup Partitions Individually" option enabled, UltraBac will image only the partition\s; not the free space.
MORE INFORMATION:
See UBQ: UBQ000186 - Image Backup and Restore Data Sheet
See UBQ: UBQ000023 – What is a File-by-File Backup
See UBQ: UBQ000027 – Restoring Individual Files from an Image Backup
See UBQ: UBQ000051 – Defining an Image Storage Device
See UBQ: UBQ000054 – Creating an Image/Partition Backup Set
See UBQ: UBQ000057 – Creating SADR (Stand Alone Disaster Recovery) Floppies - Intel & Alpha
See UBQ: UBQ000058 – Stand Alone Image Backup/Restore Using Floppies – Intel & Alpha
See UBQ: UBQ000059 – Integrated GUI Image Recovery (Non-Boot Disk)
See UBQ: UBQ000060 – Static Mirror Image Recovery
See UBQ: UBQ000061 – Stand Alone Backup & Disaster Recovery Utility
CATEGORIES:
Disaster Recovery, Registry, Restore, Setup
VERSION:
4.x to 5.x
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