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December 05, 2007
DK'08 Feature Spotlight - VSS Compatibility Mode
Over the coming weeks I'll highlight the new features and explain more about how and why they were developed. I'm starting off with one of the more obscure features which I briefly mentioned last month. This blog adds more information on the relevance of properly supporting VSS.
Let me first start off by defining Volume Shadow Copy Service (VSS). VSS is a feature first introduced, by Microsoft, with Windows Server 2003. It uses a block-level copy-on-write technology to store the bits of data that changed within a file. Then, at scheduled intervals, it takes "snapshots" of the data on a volume, storing the changes currently held. Unfortunately, without special consideration, defragmentation and VSS aren't very compatible. The issue is described in detail in a Microsoft Support Article.
Diskeeper 2008 has a new (VSS) Compatibility defrag mode. This feature will run a special defragmentation method on Volumes that have VSS enabled. This method defragments the volume is such a way to minimize the FSCTL_MOVE_FILE(mechanism in Windows used by defragmenters)/VSS conflict. During our research and development of this feature we spoke with the Microsoft NTFS and VSS developers. By implementing certain procedures, we ensured we can provide the user the performance benefits of defragments without all the negative overhead on VSS and loss of snapshots of changed data.
So why is this feature important?
If you are running Windows Vista, Windows 2003 Server or Windows Home Server you have the VSS feature. Excess VSS activity due to defragmentation without a VSS-compatible mode, will create overhead on your PC, your network, and possibly conflict with proper use of VSS itself.
WHS will enable VSS on all client systems that it is automatically backing up (does this by default). This can cause extra network traffic as all the VSS changes on the client systems are being backed up to the WHS system. For these cases, we recommend enabling the Diskeeper VSS-Compatible mode on the client systems.
Data Protection Manager (DPM) is an enterprise scaleable version of what WHS does with Vista clients. In this case DPM does this for Server 2003 clients, backing up VSS data from remote servers, across the network, into a centralized storage location.
So, if you're running Windows Vista, Windows 2003/2008 Server, Windows Home Server, or Data Protection Manager, and want to optimize the performance of your drives, Diskeeper's new feature will come in handy.
For those who want to see some technical testing results, we'll have a paper published in our Knowledge Center in the next week or so.
Posted by Michael at December 5, 2007 11:13 PM
Comments
Why cant diskeeper move the files so not all the files are on one drive?
Posted by: Pete at December 27, 2007 05:09 PM
Hi Pete,
The issue is primarily safety related. Moving files from one volume to another has some inherent risks - such as data loss from power failures.
Also keep in mind that moving files between folders and volumes can impact file attributes - a security risk. NTFS volumes allow numerous attributes that when moved between volumes can inadvertantly be changed. For example, you may restrict access to some files for Susan on volume D:, but when files from that volume are moved to volume E:, they may inherit new attributes from parent directories that allow All Users "Full Control" (and Susan can now delete the files).
Posted by: Michael at December 31, 2007 11:27 PM
Having problems after install of DK2k8 -- maybe install didn't complete well?
or maybe WINNT 5 components (running sp4 post with all MS updates ok per MS software analysis last Friday, 02/22.
Could you list, or send URL listing microsoft windows files required,
minimum file versions, file size, etc
and maybe dates of those file?
Also how do I verify product activation was completed okay? And if not, would that block coordination of mmc and diskeeper?
thanks RK
dates of
Posted by: Richard Katlavas at February 28, 2008 09:20 PM
Hi Richard,
Please contact Tech Support. It may be easier and faster for them to ask you to run an MSI install log to trace what may have caused your issue. They can help walk you through that.
Posted by: Michael at March 13, 2008 11:28 PM