diff --git a/CHANGELOG.md b/CHANGELOG.md
index 12421fb019bd2..d4ad8ef681b8a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ### Changed
 - Migrate BC libs to their FIPS counterparts ([#14912](https://github.com/opensearch-project/OpenSearch/pull/14912))
+- Increase the floor segment size to 16MB ([#17699](https://github.com/opensearch-project/OpenSearch/pull/17699))
 
 ### Dependencies
 - Bump `com.nimbusds:nimbus-jose-jwt` from 9.41.1 to 10.0.2 ([#17607](https://github.com/opensearch-project/OpenSearch/pull/17607), [#17669](https://github.com/opensearch-project/OpenSearch/pull/17669))
diff --git a/server/src/main/java/org/opensearch/index/LogByteSizeMergePolicyProvider.java b/server/src/main/java/org/opensearch/index/LogByteSizeMergePolicyProvider.java
index 0b762d781957c..1b44f910ba51b 100644
--- a/server/src/main/java/org/opensearch/index/LogByteSizeMergePolicyProvider.java
+++ b/server/src/main/java/org/opensearch/index/LogByteSizeMergePolicyProvider.java
@@ -50,7 +50,11 @@ public class LogByteSizeMergePolicyProvider implements MergePolicyProvider {
     private final Logger logger;
     private final boolean mergesEnabled;
 
-    public static final ByteSizeValue DEFAULT_MIN_MERGE = new ByteSizeValue(2, ByteSizeUnit.MB);
+    /**
+     *  Use 16MB floor size to match Lucene default.
+     *  See <a href="https://github.com/apache/lucene/pull/14189">...</a>
+     */
+    public static final ByteSizeValue DEFAULT_MIN_MERGE = new ByteSizeValue(16, ByteSizeUnit.MB);
     public static final int DEFAULT_MERGE_FACTOR = 10;
 
     public static final ByteSizeValue DEFAULT_MAX_MERGED_SEGMENT = new ByteSizeValue(5, ByteSizeUnit.GB);
diff --git a/server/src/main/java/org/opensearch/index/TieredMergePolicyProvider.java b/server/src/main/java/org/opensearch/index/TieredMergePolicyProvider.java
index d5d354c6c960a..2eeb25dee88c3 100644
--- a/server/src/main/java/org/opensearch/index/TieredMergePolicyProvider.java
+++ b/server/src/main/java/org/opensearch/index/TieredMergePolicyProvider.java
@@ -136,7 +136,13 @@ public final class TieredMergePolicyProvider implements MergePolicyProvider {
     private final boolean mergesEnabled;
 
     public static final double DEFAULT_EXPUNGE_DELETES_ALLOWED = 10d;
-    public static final ByteSizeValue DEFAULT_FLOOR_SEGMENT = new ByteSizeValue(2, ByteSizeUnit.MB);
+
+    /**
+     *  Use 16MB floor size to match Lucene default.
+     *  See <a href="https://github.com/apache/lucene/pull/14189">...</a>
+     */
+    public static final ByteSizeValue DEFAULT_FLOOR_SEGMENT = new ByteSizeValue(16, ByteSizeUnit.MB);
+
     public static final int DEFAULT_MAX_MERGE_AT_ONCE = 10;
     public static final ByteSizeValue DEFAULT_MAX_MERGED_SEGMENT = new ByteSizeValue(5, ByteSizeUnit.GB);
     public static final double DEFAULT_SEGMENTS_PER_TIER = 10.0d;