Better Edge Backup v5.2
User Guide
Copyright © 2008, Better Edge Technology, Inc. All Rights Reserved.
Page 55 of 121 (September 16, 2008)
The chapter describes what in-f ile delta technology is and how in-file delta can be used to backup large database
files (e.g. a 10GB Outlook.pst file) without uploadin g the whole database file everyday.
8.1 Overview
In-file d elta techn ology is an advanced data block matching algorithm which has the intelligence to pick up
changes (delta) of file content between two files. Using this al gorithm, daily backing up of l arge files (e.g. a 10GB
Outlook.pst file ) over low-speed internet connection is made possible because it requires only the changes of
information (should be marginal) since th e last backup to be sent over a low-speed internet connection to
complete the backup of a large file (her e we assume that the full backup of t he file has been saved on the backup
server already).
This is what will happen in the backup of a 1 0GB Outlook.pst file when it is backed up by Better Edge B ackup with
in-file delta technology.
i. The whole files (10GB), along 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 on a removable
hard disk.
ii. When backup runs again later (normally the nex t day), Better Edge Backup will download a
checksum listing of all data blocks of the full ba ckup file (or last incremental backup file) from the
backup server and use it to pick up al l changes that have been made to the current Outlook.pst
file.
iii. Changes detected are then saved in a delta file which is uploaded to the backup server. A n ew
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 du ring daily usage)
iv. Subsequent backups of this 10GB Outlook.pst file will go through step ii and step iii again. As
explained, only a small delta file and ch ecksum file will be uploaded to the backup server.
v. With in-file delta technology, daily backing up of large file over low-speed internet connection is
now possible
Incremental in-file delta type
Incremental Delta will facilitate ease o f backup. The delta i s generated by comparing with the latest upl oaded full
or delta file. The delt a file g enerated is the smallest possible and uses the least bandwidth during backu p. For
restoration, the full file an d all delta files up to the required point-in-time is required to restore the file to a
specific point-in-time.
Example: If you are adding around 100MB chang es to a 10G Outlook.pst everyday.
After the first full b ackup job, Better Edge Ba ckup will continue to generate and upload delta files instead of
uploading the full file until either one of th e following two rules are true:
a) Number of deltas generated since the last full backup is greater than the [Number of Delta] setting.
b) The delta ratio (the ratio of the delta f ile size against the full file size) is greater t han the [Delta Ratio]
setting
Using incremental delta, the delta generated by comparing the current file with the latest uploade d full or delta
file is around 100MB.
Since the delta file size is around 100MB daily, the delta ratio (around 1%) will not t rigger a full file upload.
Instead Better Ed ge Backup will continue to generate and upload de lta files until d ay 102 (assuming the full file
was uploaded on day 1) when the numbe r of deltas generated exceeds the [Number of Delta] setting a nd triggers
the upload of the full Outlook.pst file. You can di sable the [Number of Delta] and [Delta Ratio] if you don’t want to
upload the full file.