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Avoiding disk fragmentation via nshrun

Daniel Nashed  25 May 2010 06:52:44

Some of my customers are already running optimized compact operations to avoid fragmentation of their data disks with NSF.
They use a combination of compact -B and -b with the -S option to avoid recovering small amount of space from databases.

My tool nshrun already has an option to decide which compact to use based on the free space in a database.
If just a bit of space is free no compact is invoked. If just some space is free a compact -b is used if much space is free a compact -B is used.
Already in previous versions you could specify those options using -S and -s in nshrun.

But this does only reduce fragmentation to some extend. I would wish there would be an option for compact to keep some free space in the database.
There is currently no way to keep some space in the database. But I found a way to allocate some bulk space in the database in one piece which could avoid smaller allocations in the NSF would create many smaller disk fragments to be allocated. So you now can specify an amount of free space that should be in the database after compact finishes and frees space in the database.
This amount of free space is allocated in one step and would only result in at most one more fragment.

The new option is currently under test but if you are a nshrun user I am happy to send you a new version with this option to check if this helps to reduce your NSF disk fragmentation.
It will also not completely resolve all fragmentation but could potentially reduce the fragmentation a lot.

I would be also very interested to get your feedback about disk fragmentation thru NSF. I personally think there is huge potential in avoiding fragmentation.
This is not primary for Domino run-time performance but more for backup performance.

-- Daniel

Comments

1Giovanni  25.05.2010 12:42:02  Avoiding disk fragmentation via nshrun

Hello Daniel, I usually run, on windows systems, a Microsoft/SysInternal utility called "contig" with valuable results... have you already tested it?

greetings

2Daniel Nashed  25.05.2010 14:24:06  Avoiding disk fragmentation via nshrun

@Giovanni, yes we are using contig on Notes clients and also on servers. there is an OpenNTF project "DominoDefrag" (http://www.openntf.org/projects/pmt.nsf/ProjectLookup/DominoDefrag) which also leverages contig.

My solution is on top of that to avoid fragmentation. We have also customers using commercial defragmentation tools like O&O defrag with very good results.

-- Daniel

3Dietmar Dumke  25.05.2010 20:22:00  Avoiding disk fragmentation via nshrun

We run jkdefrag once weekly via Windows scheduler against the server disks. Has also some options to throttle to reduce system load while defragging. Never had problems with it since introduced.

4Andrew Luder  02.07.2010 2:52:48  Avoiding disk fragmentation via nshrun

@ Daniel,

I read your blog a month ago and you give a lot of good advice. I've just added functionality into DominoDefrag which optimizes free space between the compact and defrags stages now. Hopefully I'm finally catching up :-)

Like to meet you one day and bounce a few ideas. Perhaps I'll go to one of your seminars in Germany.

Andrew

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