[DOCS] Added 'on a single shard' to description of max_thread_count. Closes 28518
@@ -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.
