User`s guide

When this option is set to Disable, the volumes' snapshots will be taken one after the other. As a

result, if the data spans across several volumes, the resulting backup may be not consistent.

3.3.1.7 Volume Shadow Copy Service

This option is effective only for Windows operating systems.

The option defines whether a Volume Shadow Copy Service (VSS) provider—either Acronis VSS or

Microsoft VSS—has to notify VSS-aware applications that the backup is about to start. This ensures

the consistent state of all data used by the applications, in particular, completion of all database

transactions, at the moment of taking the data snapshot by Acronis Backup & Recovery 10. Data

consistency, in turn, ensures that the application will be recovered in the correct state and become

operational immediately after recovery.

The preset is: Create snapshots using VSS

Acronis Backup & Recovery 10 will select the VSS provider automatically based on the operating

system running on the machine and whether the machine is a member of an Active Directory

domain.

Create snapshots without using VSS

Choose this option if your database is incompatible with VSS. The data snapshot will be taken by

Acronis Backup & Recovery 10. Backup process is fastest, but data consistency of the applications

whose transactions are not completed at the time of taking a snapshot cannot be guaranteed. You

may use Pre/Post data capture commands (p. 56) to indicate which commands should be performed

before and after taking the snapshot, to ensure that the data is being backed up in a consistent state.

For instance, specify pre-data capture commands that will suspend the database and flush all caches

to ensure that all transactions are completed; and specify post-data capture commands that will

resume the database operations after the snapshot is taken.

Volume shadow copy writers

Before backing up the data of VSS-aware applications, make sure that the volume shadow copy

writers for those applications are turned on, by examining the list of writers that are present in the

operating system. To view this list, run the following command:

vssadmin list writers

Note: In Microsoft Windows Small Business Server 2003, the writer for Microsoft Exchange Server 2003 is

turned off by default. For instructions on how to turn it on, see the corresponding Microsoft Help and Support

article

http://support.microsoft.com/kb/838183/en.

3.3.1.8 Compression level

This option is effective for Windows and Linux operating systems and bootable media.

The option defines the level of compression applied to the data being backed up.

The preset is: Normal.

The optimal data compression level depends on the type of data being backed up. For example, even

maximum compression will not significantly reduce the archive size if the archive contains essentially

compressed files, such as .jpg, .pdf or .mp3. However, formats such as .doc or .xls will be compressed

well.