One of the things that people sometimes consider doing on their Enterprise Vault environment is to enable collections. Regular, plain, simple NTFS Collections, done by Enterprise Vault. What this does is collect together some of the files that Enterprise Vault has generated when archiving items, and put them in to a CAB file.
This has the advantage that backups can be sped up somewhat because the many, many small files are now much fewer, larger files.. and backup software likes things like that.
When enabling collections, and running them, these are the sort of events that you can see logged in the event log:
Information 28/11/2012 16:09:56 Enterprise Vault 6854 Storage File Watch
Log Name: Symantec Enterprise Vault
Source: Enterprise Vault