Differences between file-based and image-based backup
New article: 11.2020
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When scheduling backup jobs, a basic distinction must be made between file-based and image-based backup.
File-based backup
Functionality
- The backup software accesses the file system of the system to be backed up.
- The files are processed and divided into 32KB blocks, for each of these blocks a checksum is calculated.
- The checksums can be used to determine the delta in follow-on backups.
- The blocks determined for backup are compressed and encrypted.
Advantages and disadvantages
Advantages:
- BMR backup possible (Bare Metal Restore)
- Included in the standard scope of the agent, no additional plug-in is required
- No reboot required after installation
- Granular troubleshooting possible
- Files/directories can be excluded
- Script-based recovery via VPR file possible
Disadvantages:
- Slower with many small files (>20,000).
- Navigation via portal when restoring individual files
Best Practice
- For a new setup, file-based backup jobs should only be used for backing up individual files and folders.
- For existing file-based BMR backup jobs, the "Entire Server" option should be added.
- For new BMR backups, use image-based jobs.
Image-based backup
Functionality
- The backup software backs up all blocks in a volume one after another.
The image plug-in installs a changed block tracking driver. (Requires a reboot)
This can be used to determine which blocks have changed since the last backup.
- It is possible to set up a BMR backup when all system-relevant volumes are backed up.
Advantages and disadvantages
Advantages:
- BMR backup possible
- Faster with many small files
- Recommended for 1TB or more of natively protected data
- Requires less computing power than file-based backup
- Convenient restore (image is attached)
- Navigation via Explorer during restore
Disadvantages:
- No exclusion of individual files and folders possible
- Restore only possible to same size/larger disks
- Restart required after agent installation/update
- No granular troubleshooting possible
Best Practice
For protection of the entire system, including the possibility of a bare metal restore, the "Entire server" and "BMR" options should be selected.
Comparison
| Funktion | File-based backup | Image-based backup |
|---|---|---|
| BMR backup | ||
| Bootable in the cloud | ||
| Restore to same size/larger disks | ||
| Restoration to smaller disks | ||
| Included in default installation | Plugin, selected by default during installation.
Requires reboot. | |
| Files/directories can be excluded | ||
| Script-based recovery via VPR file possible | ||
| Well suited up to approx. 20,000 files | ||
| Recommended above 1TB natively protected data volume | ||
| Navigation during the recovery of individual files | via Portal |
via Explorer |