Another white paper available, this time provided by IBM: Exchange 2003 VSS Snapshot Backup Whitepaper. If you are using IBM storage, this Technical Solution Guide demonstrates how to install & configure a Microsoft Exchange Server 2003 VSS-based backup & recovery solution using Tivoli Storage Manager on the DS6000 & DS8000.
A problem in the past was that each vendor's point-in-time copy method had its own unique proprietary interface. Microsoft Developed Volume Shadow Copy Services (VSS) as a common interface front-end to resolve this concern. IBM Tivoli Storage Manager for Mail can invoke standard VSS interfaces, and this in turn can invoke FlashCopy on the IBM System Storage SAN Volume Controller, DS8000 series, or DS6000 series disk system.
You might be thinking: Wouldn't it have been less effort to just have TSM for Mail invoke IBM proprietary interfaces, rather than having to put full VSS support into TSM for mail, and then full VSS support into IBM's various disk systems? Perhaps, but IBM doesn't decide to do things because it is the cheapest way, we focus on what is the right way, and in this case, customers now have more choices, then can use TSM for Mail with IBM or non-IBM disk systems that support the VSS interface, and IBM disk systems can be employed into other uses for VSS snapshot.