Re: Unable to force lucena spinning disk detection

[Chris Hostetter <ho...@fucit.org>]

: Lucene is detecting our SSDs as Spinning disks, as seen through the admin metrics endpoint:
: 
: 
:   *   CONTAINER.fs.coreRoot.spins: true
:   *   CONTAINER.fs.spins: true

the spins metric is always going to return whatever the Lucene IOUtils 
think the disk is -- there is no setting you can use to override that and 
make the metric "lie" (from it's perspective) about what lucnee thinks

*BUT* ... what lucene thinks only matters in terms of the *DEFAULT* 
behavior when configuring ConcurrentMergeScheduler...

: However we can see in the `system.properties` endpoint we are overriding it:
: 
: 
:   *   lucene.cms.override_spins: "false"

...with that property set, and use ConcurrentMergeScheduler, then it's 
default behavior will be to pick "MaxMergesAndThreads" based on hueristics 
accordingly.

If you don't use ConcurrentMergeScheduler, or have explicitly configured 
the MaxMergesAndThreads, then that system property won't matter.

(but either way, the *.spins metrics are going to tell you what lucene 
things the disk is)

FWIW: Instead of focusing on setting lucene.cms.override_spins to override 
the spins/ssd hueristics, you may want to just focus on explicitly setting 
the max merges and threads explicitly since that gives you more direct 
control ... in 9.x the spins hueristic will go away entirely and the same 
defaults are used entirely regardless.



-Hoss
http://www.lucidworks.com/