In-file delta technology is an advanced data block matching algorithm with the intelligence to pick up changes (delta) of file content between two files.
Using this algorithm, daily backup of large files over low-speed internet connection is made possible because it requires only the changes of information since the last backup to be sent over (assuming that the full backup of the file has been saved on the backup server already).
This is what will happen in the backup of a 10 GB Outlook.pst file when it is backed up by Servosity Pro with In-file delta technology:
- The whole file (10 GB) with its checksum file, are backed up to the backup server. This can be done directly through the internet or indirectly using the seed loading utility.
- When the backup runs again later (sub-sequence backup), Servosity Pro will download a checksum listing of all data blocks of the full backup file (or last incremental backup file) from the backup server and use it to pick up all changes that have been made to the current Outlook.pst file.
- Changes detected are then saved in a delta file which is uploaded to the backup server. A new checksum file is generated and is also uploaded. (This delta file is assumed to be small because the content of PST files doesn't change a lot during daily usage).
- Sub-sequent backups of this 10 GB Outlook.pst file will go through step 2 and step 3 again. As explained, only a small delta file and checksum file will be uploaded to the backup server.
- With In-file delta technology, daily backing up of large file over low-speed internet connection is now possible.
Incremental In-file delta
Incremental Delta will facilitate ease of backup. The delta is generated by comparing with the last uploaded full or delta file. Delta generated with this method is smaller and uses the least bandwidth. However, for restoration, the full file and all deltas up to the required point-in-time are required to be restored and merged.
Differential In-file delta
Differential Delta will facilitate ease of restore. The delta is generated by comparing with the last uploaded full file only. Delta generated with this method will grow daily and uses more bandwidth. However, for restoration, the full file and a single delta is required to be restored and merged.