# Cluster vs. Index Segment Size Settings Precedence for max\_merged\_segment

**URL:** <https://discuss.elastic.co/t/cluster-vs-index-segment-size-settings-precedence-for-max-merged-segment/375694>\
**Category:** Elasticsearch\
**Created:** [March 11, 2025, 10:31am UTC](https://discuss.elastic.co/t/cluster-vs-index-segment-size-settings-precedence-for-max-merged-segment/375694 "2025-03-11T10:31:30Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Saleh\_AbuAli](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/saleh_abuali/32/141444_2.png) [@Saleh\_AbuAli](https://discuss.elastic.co/u/Saleh_AbuAli)\
**Post date:** [March 11, 2025, 10:31am UTC](https://discuss.elastic.co/t/cluster-vs-index-segment-size-settings-precedence-for-max-merged-segment/375694/1 "2025-03-11T10:31:30Z")

</div>

I've noticed what appears to be cluster settings taking precedence over index-specific settings for segment size limits, and I'm seeking clarification on how these settings interact.

My index settings explicitly specify:

```auto
"merge": {
  "policy": {
    "max_merged_segment": "0b",
    "segments_per_tier": "10.0"
  }
}

```

While my cluster settings specify:

```auto

"merge": {
  "policy": {
    "max_merged_segment": "5gb",
    "max_time_based_merged_segment": "100gb"
  }
}

```

-I noticed that despite the index setting `max_merged_segment=0b` (which should mean unlimited), all segments consistently cap at ~5.3GB  
Questions

1. Is it expected that cluster-level `max_merged_segment` settings take precedence over index-level settings?
2. Does setting `max_merged_segment=0b` at the index level not actually mean "unlimited" as I expected?
3. Why are my segments capping at ~5.3GB when the cluster setting is 5GB? Is there some overhead calculation?
4. Is this precedence behavior documented somewhere I might have missed?