What are the benefits or drawbacks of using Microsoft Data Protection Manager (DPM) to back up Hyper-V virtualized servers instead of a third party backup software product?
Microsoft Data Protection Manager is a near-CDP product. Near-CDP is close to continuous data protection (CDP), where it's not truly continuous, it's something like once an hour. First off, DPM fully integrates everything I described about VSS implementation -- for obvious reasons -- it's put out by Microsoft. That's the first advantage. You can be assured of complete integration and that they're going to talk to all the VSS writers.
The second thing is that when you compare it to traditional third-party backup apps, those are traditional full and incremental backup apps. Even when we look at IBM Corp. Tivoli Storage Manager (TSM), which offers a progressive incremental feature, it does that only for file systems. When we look at doing data backups of databases and applications inside VMs, VMware also does full and incremental backups. So when you compare Data Protection Manager to the typical backup app, the typical backup app is going to create full and incremental backups. The only thing DPM does each time you create a snapshot is that it transfers the byte that it changed from the snapshot that was taken previously. And so it's a very incremental-forever block-level technology. So there are two things to remember about using DPM with Hyper-V. First, it should have very little impact on the performance of Hyper-V, and second, it should have very tight integration with Windows because it's made by Microsoft.
What are the challenges with using a third-party backup tool?
The biggest thing to remember when using a third-party data backup tool is to make sure that it fully integrates with VSS. Also, make sure that it's talking to all the VSS writers. Everyone's going to want to talk to Exchange and Sequel Server, but what about Active Directory, and Oracle? There are several other smaller VSS writers that aren't as popular. Are there other applications that are present in the virtual machines, and do they have a VSS writer? And is my backup app talking to all the VSS writers? The proper way for a backup to behave is to do a metadata query of VSS. VSS should give you a list of all the VSS writers that it has. It should then talk to each of the VSS writers that it discovers in the process. And so hopefully it's able to discover all those, and hopefully it's able to talk to them so each of the VSS writers can do the right thing. These are all things that you simply need to verify with documentation and testing.
Many companies incorporate 
