Friday, December 3, 2010

File or Volume defrag! What's the best?

Often people have asked us about the benefits of Defrag.NSF over any of the commercially available "Volume" style defraggers, and some have even been surprised when we showed them how the free defragger they were using wasn't actually doing as well as they though it was.

That is always the easy part for us, as the back to back results and the straight forward flexibility and configuration options available in Defrag.NSF just leave no doubt, it's just too easy!

The real answer is that it all depends on what you want to do.

What I do know is that there are a lot of different ways to defragment a Volume. Some common methods include; systematically defragmenting all the files, reordering the files, consolidating the freespace as tight as possible, consolidating freespace wherever possible. The list goes on.....

Volume defragmentation can be I/O expensive, particularly on a Domino volume that is fragmenting rapidly due to data change, not only that but it is not always the best approach to dealing with fragmentation on a Domino server, for example a completely defragged volume with no free-space allocated to individual files will re-fragment the individual files quite quickly. Defrag.NSF's pre-allocation of freespace can help here and this is one big advantage of Defrag.NSF, an advantage that is almost always overlooked by people using "Volume" type defraggers. In fact it becomes a vicious cycle requiring inefficient full Volume defrags at overly frequent intervals - not ideal at all!

Surprisingly, there are also a number of different ways to defragment an individual file, but most file defraggers will just simplistically look for a freespace block big enough to hold a file and move it there.

So what do we do in Defrag.NSF?

Defrag.NSF is able to intelligently utilise both File and Volume defragmentation and switches between the two seamlessly as required to achieve the desired result, again here is a big advantage over traditional "Volume" derfaggers. Where possible, Defrag.NSF tries to do a file move, if the file is large, Defrag.NSF analyses the MFT, works out where its fragments are, and then reassembles them as efficiently as it can. This feature allows the product to defrag multi-gigabyte files quickly.

If there still isn't enough freespace, Defrag.NSF can then consolidate the Volume until there is. The system does this automatically and intelligently.

So File or Volume defrag? What's the best? ... Let Defrag.NSF decide...

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