HP SureStore AutoBackup Administrator's Guide - Not Orderable

Eliminating redundant data
HP SureStore AutoBackup uses a number of techniques to eliminate redundant data
from its backups:
It excludes some files and directories.
It only backs up common files once (redundant file elimination).
It backs up a baseline version for all new files, and subsequently only backs up
those parts of the file that have been modified.
Exclude files
On a client's machine, there will be files, such as temporary files, Internet cache files
and the swap file, which do not need to be backed up. HP SureStore AutoBackup
provides the facility to exclude directories from the backup. The default policy for
excluding files is controlled from the Advanced Administrator Console. You can also
allow users to define their own set of excluded files or directories from the Configure
Backup Options tab.
Note: If you do decide to change the default settings, particularly if you allow users to
define settings, you may limit the capacity of the appliance so that it supports fewer
clients.
Common files
Files for backup will include new data and modified data that is unique to that client
and other files, such as applications that are common to many clients. The underlying
database enables HP SureStore AutoBackup to check for common files. If the date
signature on the common files matches, it does not back these files up again, but just
marks the client's index entry so that the common files will be included in any restore.
Multiple versions
For new files, HP SureStore AutoBackup carries out a 'baseline' backup, which writes
the full amount of data to the AutoBackup appliance (after breaking the file down into
a number of blocks, which are indexed on the integrated SQL Server database). With
modified files, only those blocks that have changed are backed up and the index on the
database is updated so that modified blocks can be tracked with the unchanged blocks.
This is termed block-level incremental backups or versioning. The use of the database
index ensures that HP SureStore AutoBackup can always rebuild the blocks to restore
the correct version of a file for a given date.
The following example illustrates how HP SureStore AutoBackup eliminates
redundant data.
Capacity, How To Manage
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