A Retrospective on Microsoft VSS and System Center Data Protection Manager

A Retrospective on Microsoft VSS and System Center Data Protection Manager

For the first ten or so years that Windows Server was backed up, most backup vendors had to figure out their own ways to access the SQL databases, the Exchange mail stores, and the Windows file system. And then came Volume Shadow Copy Services (VSS), albeit slower than you might recall.

VSS provides the underpinning by which almost all Windows backups occur:

  • VSS Writers are built into most applications. When asked, they ensure that the applications (or the Hyper-V host or Windows file system) are “back-up-able” by queiscing live data, checkpointing transaction logs, etc.

     

  • VSS Requesters are part of most backup application agents. They talk to the VSS Writers when the backup job starts and stops.

     

  • VSS Providers are built into storage hardware and storage software. They store the static access to the data provided by the VSS Writers within the applications.

Today, most backup vendors wouldn’t dream of backing up a Windows OS/VM or its applications without using VSS. But it wasn’t always that way. When VSS first launched during the Windows Server 2003 timeframe, it wasn’t immediately embraced by the backup vendor community – first because of doubt, then out of concern due to the lack of differentiation in usage, and finally just because it took a while to reinvent how the APIs would be interacted with.

That got me reminiscing about System Center Data Protection Manager (DPM). I joined Microsoft in 2005 to help launch and lead that product – and I stayed through DPM 2010’s release. As I shared publicly at many Microsoft TechEd conferences between 2006 and 2010, I believe Microsoft never intended to be a full-fledged backup software provider – i.e., a complete competitor to the large Windows backup companies such as Symantec, CommVault, or EMC. But Microsoft and DPM did bring unique value to “backup” and still do today.

The single best thing that DPM ever did was to improve VSS. Before DPM, Microsoft incorporated significant innovations into VSS. But because Microsoft did not have an in-depth understanding of how the backup software vendors (i.e., the ISVs) were interacting with VSS, there was a gap resulting in occasional finger-pointing on both sides. In contrast, when DPM had issues with VSS, Microsoft’s engineers could collaborate fully and transparently. VSS was enhanced accordingly, based on the lessons learned through DPM, and the rest of the backup community benefitted from a more robust VSS framework.

The most significant value that DPM did and does provide is incremental value to the System Center suite. Originally, every component of System Center was a separate for-sale offering with separate server and agent licenses. Today, it is sold in suite-only form. Thinking analogously of the MS Office suite, DPM may not be the “Excel” or “Word” of the System Center suite, but it is System Center’s “Access.” Not all SysCtr users jump into DPM like they do with Operations Manager; some use something else for those ancillary functions, and some use it occasionally for certain workloads/scenarios (perhaps in branch offices or as additional protection before a migration). Others jump into DPM just as data junkies jump into Access to leverage its huge capabilities beyond run-of-the-mill document, presentation, and spreadsheet development.

The most important job of DPM – and the other Microsoft backup utilities/services – is to ensure high satisfaction with Windows as a platform. After all, if a platform (any platform) is not reliably protectable and recoverable, many organizations and individuals won’t even consider it. The DPM evolution proceeded as follows:

  • Before VSS was “the standard,” DPM provided at least one way to ensure a Microsoft-supported backup and restoration of core Microsoft workloads because non-VSS methods were often troublesome or were believed to induce corruption during restoration.

  • In DPM’s early years, it provided a solution for protecting new workloads as platforms first launched, e.g., for Exchange 2010 (early-adopter previews), SharePoint 2007, and SharePoint 2010.

  • Today, regardless of what else you might use for particular workloads, DPM provides a robust backup solution for the Windows Server-centric parts of your IT environment including Hyper-V implementations, and it is “built-in without additional charge” for those organizations using System Center for management or monitoring of Windows environments.

Along the way, DPM continues to help spearhead the evolution of VSS for on-premises backup, as well as the backup-related utilities and mechanisms coming in Microsoft’s cloud platforms and their backup capabilities. Said another way, with deliberate nostalgia … “Is DPM your primary backup solution across your organization? Maybe not. But if your backup solution relies on VSS, you have DPM (then and now) to thank.”

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