Secrets of the Administration Guild: New Compacting Options

[eknori]

http://www.leadershipbynumbers.com/ms.nsf/d6plinks/BMAA-849P4W

Jack Dausman   

ND8.5 has added lots of new functionality, but not all of it is well documented. Because I haven't written any "Secrets" for a bit, I thought this would be the right opportunity to explain a new configuration: DEBUG_ENABLE_COMPACT_8_5=1. I've run it on AIX, Linux and Win2008 Domino servers.

The new setting is dynamic, so it will be active very quickly. To ensure that it's working correctly, use a console command to read the advanced setting: "load compact -help." Reviewing the console help, you'll see several additional parameters:

        * W nn - Only compact databases which haven't been compacted successfully in the last nn days.
        * w - Exclude system databases (e.g., log.nsf, names.nsf).
        * X nn - Limit each database compaction to no more than nn minutes. (Applies to in-place compaction only)
        * x nn - Limit total compaction time to nn minutes.
        * # nn - Execute up to nn compactions in parallel using different threads.



There are some caveats to keep in mind with these settings. It is possible to achieve some dramatic improvements in compacting throughput by employing the "#" configuration. But, there is a cautionary recommendation to not exceed eight threads, as Domino will run into the ground with database I/O and CPU bottlenecks.

The "w" is one of those About Time settings. To date, the only alternative has been to create an indirect file with a listing of all the root databases that could be safely compacted. The "w" is not perfect--it will try to run against the events4.nsf, and that's going to create a compaction error. However, I've never seen the "w" compaction interrupt the Events task, so the error is only an annoyance. On the other hand, I've certainly seen the AdminP task halt because someone tried to compact adminp.nsf.

So, if your Domino server is up-to-date, then you should be ready to optimize your compacting.