What is Microsoft VSS and why is it so important to virtual server backup?
VSS stands for the Volume Shadow Copy Service. Microsoft VSS is important for two main reasons. First, it provides the ability to back up a virtual Windows Server while the server is running. Without VSS it is often necessary to place virtualized Windows Servers into a saved state prior to creating a snapshot backup.
The other reason why VSS is important is because it helps with application consistency. If for example, you were to make a snapshot backup of an Exchange mailbox server without using VSS then there is a high likelihood that the database contents would change during the backup process. The end result would be an inconsistent (and probably corrupt) backup. VSS works with certain applications to ensure that they are backed up in a way that maintains application consistency.
This was first published in April 2012