No, I mean backup the vault store partition. There is a section in the Admin guide about backups, I recommend you give that a read. The backup software needs to remove the archive bit attribute off the files, otherwise you will need to use the trigger.
Here is a nice article that overviews it:
https://www-secure.symantec.com/connect/articles/changes-backup-procedures-enterprise-vault-8
as well as this:
http://seer.entsupport.symantec.com/docs/312327.htm