Wednesday, November 9, 2011

Defragging FT indexes - little benefit for lots of work!

Many customers ask us about the defragging of Full Text Indexes and now with the 8.5.3 notes.ini setting FTBasePath the Full Text Indexes, and defragging them, seems to be back on many admins' radar. But before you go on a defragging FT campaign, you just might want to rethink if it is worth the effort - let's explain.

Full Text index files are stored under a sub-directory for a given NSF file. The contents of which are updated by the Domino Server and the indexer (Update) tasks. This update frequency is controlled by various factors and can occur at anytime from immediate to daily. When the index is updated it just about always fragments the index files. You can have a perfectly defragged index and have it re-fragment within seconds. This will keep happening over and over again.

So what effect on performance does a fragmented FT index have? Well from our testing, little to nothing, a couple of milliseconds here and there. Certainly not perceptible to the average user performing a search.

Now on top of all this, the FT files are not normally candidates for backing up so even then there are none of the backup benefits that defragging usually returns.

On busy servers with 1000s of users with indexed mail files and various other databases indexed for searching, the associated FT index files can account for many GB of data, since these files are also quite regularly heavily fragmented there is the potential for wasting significant time and server resources in defragging them for no return in the user search experience.

This appears to be a case where effort does not = reward !!

So what do we recommend you do ?

Well if you want you can get Defrag.NSF to defrag a Full text Index associated with a database, by selecting the FT Index option on the Processing schedule tab.

But alternatively the administrator could choose to schedule defragging of all the Full Text Indexes on a separate drive if the notes.ini setting FTBasePath has been implemented. That way the indexes could be optimised once a week (or even daily if you wish) and they are not going to fragment the freespace that can be better used by the NSF file

For more information on Defragging Domino Servers check out our web site at

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