# Unable to set index.merge.scheduler.max\_thread\_count

**URL:** <https://discuss.elastic.co/t/unable-to-set-index-merge-scheduler-max-thread-count/101161>\
**Category:** Elasticsearch\
**Created:** [September 20, 2017, 12:23pm UTC](https://discuss.elastic.co/t/unable-to-set-index-merge-scheduler-max-thread-count/101161 "2017-09-20T12:23:04Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![itplayer](https://avatars.discourse-cdn.com/v4/letter/i/d26b3c/32.png) [@itplayer](https://discuss.elastic.co/u/itplayer)\
**Post date:** [September 20, 2017, 12:23pm UTC](https://discuss.elastic.co/t/unable-to-set-index-merge-scheduler-max-thread-count/101161/1 "2017-09-20T12:23:04Z")

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According to official document said, if we unfortunately still use spin disk, we should set this value to 1.  
I used to be set this in elasticsearch.yml but not luck in v5.4

I know this setting has been move to index level, what I confused is, if this is per index setting? What happened if I create two indices and set this value to different in each indices?

Can anyone help to guide?  
Thanks.

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**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [September 21, 2017, 2:06am UTC](https://discuss.elastic.co/t/unable-to-set-index-merge-scheduler-max-thread-count/101161/2 "2017-09-21T02:06:44Z")

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> [@itplayer](#):
>
> if this is per index setting? What happened if I create two indices and set this value to different in each indices?

Then they will have different merge settings.

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<div class="post-metadata">

**Author:** ![itplayer](https://avatars.discourse-cdn.com/v4/letter/i/d26b3c/32.png) [@itplayer](https://discuss.elastic.co/u/itplayer)\
**Post date:** [September 21, 2017, 9:43am UTC](https://discuss.elastic.co/t/unable-to-set-index-merge-scheduler-max-thread-count/101161/3 "2017-09-21T09:43:38Z")

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So merge scheduler is per shard? since each shard is actually a Lucene writer?  
If a node with 2 indices, index A set max\_thread\_count=1, index B set max\_thread\_count=2. We will have 3 threads running when doing merge right?  
I thought this is node setting.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [October 19, 2017, 9:43am UTC](https://discuss.elastic.co/t/unable-to-set-index-merge-scheduler-max-thread-count/101161/4 "2017-10-19T09:43:42Z")

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