diff --git a/docs/reference/index-modules/merge.asciidoc b/docs/reference/index-modules/merge.asciidoc index 97db09ba656c7..cc0613ec2870d 100644 --- a/docs/reference/index-modules/merge.asciidoc +++ b/docs/reference/index-modules/merge.asciidoc @@ -23,7 +23,8 @@ The merge scheduler supports the following _dynamic_ setting: `index.merge.scheduler.max_thread_count`:: - The maximum number of threads that may be merging at once. Defaults to + The maximum number of threads on a single shard that may be merging at once. + Defaults to `Math.max(1, Math.min(4, Runtime.getRuntime().availableProcessors() / 2))` which works well for a good solid-state-disk (SSD). If your index is on spinning platter drives instead, decrease this to 1.