Better edge backup v5.2 – Deonet Backup Solutions 5.2.7.0 User Manual

Page 56

Better Edge Backup v5.2

User Guide

Page 56 of 121

(September 16, 2008)

All delta files are generated with respect to changes made since the last incremental or full backup. This means
that the last full backup file and ALL incremental delta backup files are required to restore the latest snapshot of a
backup file.

Differential in-file delta type

Differential Delta will facilitate ease of restore. The delta is generated by comparing with the latest uploaded full
file. The delta file generated grows daily and uses more bandwidth during backup. For restoration, the full file and
a single delta file is required to restore the file to a specific point-in-time.

Example: If you are adding around 100MB changes to a 10G Outlook.pst everyday.

After the first full backup job, Better Edge Backup will continue to generate and upload delta files instead of
uploading the full file until either one of the following two rules are true:

Number of deltas generated since the last full backup is greater than the [Number of Delta] setting.

The delta ratio (the ratio of the delta file size against the full file size) is greater than the [Delta Ratio]
setting

Using differential delta, the delta generated by comparing the current file with the latest uploaded full file is
around 100MB for the 1

delta, 200MB for the 2

delta, 300MB for the 3

delta and so on.

Since the delta file grows by 100MB daily, the delta ratio for day 52 (delta file size is approximately 51x100=
5.1GB, assuming the full file was uploaded on day 1) being over 50% exceeds the [Delta Ratio] setting and
triggers the upload of the full Outlook.pst file. You can disable the [Number of Delta] and [Delta Ratio] if you don’t
want to upload the full file.

All delta files are generated with respect to changes made since the last full backup file (i.e. differential backup).
This means that only last full backup file and the last delta file are required to restore the latest snapshot of a
backup file. This means that other intermediate delta files are only required if you want to restore other snapshots
of a backup file.

Differential in-file delta backup has the benefits that a corrupted delta file would only make one particular version
of a backup file non-recoverable and all other backups created by other delta files of the same file would still be
intact.