Backup Considerations

To run successful backups consider the following:

If you perform a full backup of component A, and then a full backup of A's child component B, the differential backup of component A would fail. In other words, a Farm-level full backup can be followed by a Farm-level differential. However, you cannot do a Farm-level full backup followed by a SharePoint Provider Service full backup, and then a Farm Differential backup. In this case, the differential job would fail with an error message.
You cannot perform a backup by using both SharePoint Server 2007 and tools such as Microsoft SQL Server tools, Central Administration website, and so on. For example, if you perform a full backup using these tools, you may not be able to restore the differential backup job.
If you try to protect SharePoint Server 2007 using the Agent for SharePoint and other agents, such as Client Agent and Agent for SQL server, the SharePoint 2007 data may be backed up more than once. To avoid this situation, you should exclude the SharePoint 2007 database and files from the Client Agent and Agent for SQL Server backup job.

SharePoint Server 2007 does not support the following:

Data encryption and compression at the agent side under the Global Options.
Multiplexing and Multistreaming backup jobs.
Backup agent data on two different machines that are in different CA ARCserve Backup domain.