Roughly five years ago, I wrote a book titled "Enterprise Storage Solutions" that centered on the latest and greatest in disaster recovery methodology: SANs, NAS devices, Fibre Channel, robotic arm tape libraries -- the works. With disk space getting cheaper and cheaper, solutions such as backup-to-disk-to-tape were all the rage.
Microsoft, not to be left out, introduced storage enhancements with Windows 2000 such as the Removable Storage Manager (RSM), the Remote Storage Service (RSS), reparse points, volume mount points, Windows File Protection (WFP), the Indexing Service, Sparse files, Single Instance Storage (SIS), File Replication Service (FRS), and the Distributed File System (DFS).
But the technology continued to evolve in both large and small ways. For example, Volume Shadow Copies (also called Volume Snapshot Service or VSS or Previous Versions) is a technology introduced in Windows XP SP1 (and available in subsequent products) that provides the ability to take a snapshot of your data to provide a restore point back to a specific moment in time.
VSS continues to evolve, and we need to stay up on the latest improvements with each server and client OS. The storage team at Microsoft invested a lot of time to improve the VSS services in Server 2008 and Vista SP1. For example, in Server 2008 there is a new VSS requester (which is used to create and manage shadow copies) called Diskshadow. There are also new or updated writers for Server 2008 and Vista SP1. Read more about this from the storage team blog site.
With some of the enhancements made in terms of high-availability solutions, some experts have asked the question, "Are backups obsolete?" Consider, for example, approaches that are possible with Exchange 2007. If you use some of the "free" high-availability solutions such as Cluster Continuous Replication combined with Standby Continuous Replication -- and throw in some of the enhancements to features such as database portability and recovery storage groups -- you might be able to get away with a backup-free world (at least with Exchange)!
Is Microsoft saying you should stop backing up Exchange? Not quite -- although the fact that Server 2008 is the first release of the product line that doesn't allow you to automatically perform backups of Exchange could be an indication of the direction the company is leaning. The idea may make you feel a bit nervous, in which case you may look at more cost-effective backup/recovery software for your environment to supplement your high-availability implementations -- especially if you want to perform VSS backups of the passive side to your HA solution. Hey, it never hurts to have a spare tire -- even if you have guarantees of 40,000 miles on the brand-new ones you just bought.