diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index 1a85a9c5127..80b949fe11b 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -107,6 +107,8 @@ New Features
 
 * SOLR-13569: AdminUI visual indication of prod/test/dev environment (janhoy)
 
+* SOLR-12554: Expose IndexWriterConfig's ramPerThreadHardLimitMB through solrconfig.xml (Ishan Chattopadhyaya, Munendra S N)
+
 Bug Fixes
 ----------------------
 
diff --git a/solr/core/src/java/org/apache/solr/update/SolrIndexConfig.java b/solr/core/src/java/org/apache/solr/update/SolrIndexConfig.java
index 42f893765ea..0bdfe84f073 100644
--- a/solr/core/src/java/org/apache/solr/update/SolrIndexConfig.java
+++ b/solr/core/src/java/org/apache/solr/update/SolrIndexConfig.java
@@ -67,6 +67,7 @@ public class SolrIndexConfig implements MapSerializable {
   public final int maxBufferedDocs;
 
   public final double ramBufferSizeMB;
+  public final int ramPerThreadHardLimitMB;
 
   public final int writeLockTimeout;
   public final String lockType;
@@ -85,6 +86,7 @@ public class SolrIndexConfig implements MapSerializable {
     useCompoundFile = false;
     maxBufferedDocs = -1;
     ramBufferSizeMB = 100;
+    ramPerThreadHardLimitMB = -1;
     writeLockTimeout = -1;
     lockType = DirectoryFactory.LOCK_TYPE_NATIVE;
     mergePolicyFactoryInfo = null;
@@ -130,6 +132,9 @@ public class SolrIndexConfig implements MapSerializable {
     maxBufferedDocs=solrConfig.getInt(prefix+"/maxBufferedDocs",def.maxBufferedDocs);
     ramBufferSizeMB = solrConfig.getDouble(prefix+"/ramBufferSizeMB", def.ramBufferSizeMB);
 
+    // how do we validate the value??
+    ramPerThreadHardLimitMB = solrConfig.getInt(prefix+"/ramPerThreadHardLimitMB", def.ramPerThreadHardLimitMB);
+
     writeLockTimeout=solrConfig.getInt(prefix+"/writeLockTimeout", def.writeLockTimeout);
     lockType=solrConfig.get(prefix+"/lockType", def.lockType);
 
@@ -179,6 +184,7 @@ public class SolrIndexConfig implements MapSerializable {
     Map<String, Object> m = Utils.makeMap("useCompoundFile", useCompoundFile,
         "maxBufferedDocs", maxBufferedDocs,
         "ramBufferSizeMB", ramBufferSizeMB,
+        "ramPerThreadHardLimitMB", ramPerThreadHardLimitMB,
         "writeLockTimeout", writeLockTimeout,
         "lockType", lockType,
         "infoStreamEnabled", infoStream != InfoStream.NO_OUTPUT);
@@ -221,6 +227,10 @@ public class SolrIndexConfig implements MapSerializable {
     if (ramBufferSizeMB != -1)
       iwc.setRAMBufferSizeMB(ramBufferSizeMB);
 
+    if (ramPerThreadHardLimitMB != -1) {
+      iwc.setRAMPerThreadHardLimitMB(ramPerThreadHardLimitMB);
+    }
+
     iwc.setSimilarity(schema.getSimilarity());
     MergePolicy mergePolicy = buildMergePolicy(core.getResourceLoader(), schema);
     iwc.setMergePolicy(mergePolicy);
diff --git a/solr/core/src/test-files/solr/collection1/conf/solrconfig.snippet.randomindexconfig.xml b/solr/core/src/test-files/solr/collection1/conf/solrconfig.snippet.randomindexconfig.xml
index 8f90d26273d..20ddf96df42 100644
--- a/solr/core/src/test-files/solr/collection1/conf/solrconfig.snippet.randomindexconfig.xml
+++ b/solr/core/src/test-files/solr/collection1/conf/solrconfig.snippet.randomindexconfig.xml
@@ -32,6 +32,7 @@ A solrconfig.xml snippet containing indexConfig settings for randomized testing.
 
   <maxBufferedDocs>${solr.tests.maxBufferedDocs}</maxBufferedDocs>
   <ramBufferSizeMB>${solr.tests.ramBufferSizeMB}</ramBufferSizeMB>
+  <ramPerThreadHardLimitMB>${solr.tests.ramPerThreadHardLimitMB}</ramPerThreadHardLimitMB>
 
   <mergeScheduler class="${solr.tests.mergeScheduler}" />
 
diff --git a/solr/core/src/test-files/solr/configsets/_default/conf/solrconfig.xml b/solr/core/src/test-files/solr/configsets/_default/conf/solrconfig.xml
index fd1d94c803f..f5ffe08b554 100644
--- a/solr/core/src/test-files/solr/configsets/_default/conf/solrconfig.xml
+++ b/solr/core/src/test-files/solr/configsets/_default/conf/solrconfig.xml
@@ -163,6 +163,15 @@
     <!-- <ramBufferSizeMB>100</ramBufferSizeMB> -->
     <!-- <maxBufferedDocs>1000</maxBufferedDocs> -->
 
+    <!-- Expert: ramPerThreadHardLimitMB sets the maximum amount of RAM that can be consumed
+         per thread before they are flushed. When limit is exceeded, this triggers a forced
+         flush even if ramBufferSizeMB has not been exceeded.
+         This is a safety limit to prevent Lucene's DocumentsWriterPerThread from address space
+         exhaustion due to its internal 32 bit signed integer based memory addressing.
+         The specified value should be greater than 0 and less than 2048MB. When not specified,
+         Solr uses Lucene's default value 1945. -->
+    <!-- <ramPerThreadHardLimitMB>1945</ramPerThreadHardLimitMB> -->
+
     <!-- Expert: Merge Policy
          The Merge Policy in Lucene controls how merging of segments is done.
          The default since Solr/Lucene 3.3 is TieredMergePolicy.
diff --git a/solr/core/src/test/org/apache/solr/core/TestConfig.java b/solr/core/src/test/org/apache/solr/core/TestConfig.java
index 57c22234821..69882c66e58 100644
--- a/solr/core/src/test/org/apache/solr/core/TestConfig.java
+++ b/solr/core/src/test/org/apache/solr/core/TestConfig.java
@@ -154,6 +154,7 @@ public class TestConfig extends SolrTestCaseJ4 {
     ++numDefaultsTested; assertEquals("default maxBufferedDocs", -1, sic.maxBufferedDocs);
 
     ++numDefaultsTested; assertEquals("default ramBufferSizeMB", 100.0D, sic.ramBufferSizeMB, 0.0D);
+    ++numDefaultsTested; assertEquals("default ramPerThreadHardLimitMB", -1, sic.ramPerThreadHardLimitMB);
     ++numDefaultsTested; assertEquals("default writeLockTimeout", -1, sic.writeLockTimeout);
     ++numDefaultsTested; assertEquals("default LockType", DirectoryFactory.LOCK_TYPE_NATIVE, sic.lockType);
 
@@ -215,7 +216,7 @@ public class TestConfig extends SolrTestCaseJ4 {
     Assert.assertEquals(-1, solrConfig.getUpdateHandlerInfo().autoCommmitMaxTime);
   }
 
-  // sanity check that sys propertis are working as expected
+  // sanity check that sys properties are working as expected
   public void testSanityCheckTestSysPropsAreUsed() throws Exception {
 
     SolrConfig sc = new SolrConfig(new SolrResourceLoader(TEST_PATH().resolve("collection1")), "solrconfig-basic.xml", null);
@@ -224,10 +225,10 @@ public class TestConfig extends SolrTestCaseJ4 {
     assertEquals("ramBufferSizeMB sysprop", 
                  Double.parseDouble(System.getProperty("solr.tests.ramBufferSizeMB")), 
                                     sic.ramBufferSizeMB, 0.0D);
+    assertEquals("ramPerThreadHardLimitMB sysprop",
+        Integer.parseInt(System.getProperty("solr.tests.ramPerThreadHardLimitMB")), sic.ramPerThreadHardLimitMB);
     assertEquals("useCompoundFile sysprop", 
                  Boolean.parseBoolean(System.getProperty("useCompoundFile")), sic.useCompoundFile);
   }
 
 }
-
-
diff --git a/solr/core/src/test/org/apache/solr/update/SolrIndexConfigTest.java b/solr/core/src/test/org/apache/solr/update/SolrIndexConfigTest.java
index d5ebf051d9f..de5944edb45 100644
--- a/solr/core/src/test/org/apache/solr/update/SolrIndexConfigTest.java
+++ b/solr/core/src/test/org/apache/solr/update/SolrIndexConfigTest.java
@@ -179,6 +179,8 @@ public class SolrIndexConfigTest extends SolrTestCaseJ4 {
 
     ++mSizeExpected; assertTrue(m.get("ramBufferSizeMB") instanceof Double);
 
+    ++mSizeExpected; assertTrue(m.get("ramPerThreadHardLimitMB") instanceof Integer);
+
     ++mSizeExpected; assertTrue(m.get("writeLockTimeout") instanceof Integer);
 
     ++mSizeExpected; assertTrue(m.get("lockType") instanceof String);
diff --git a/solr/server/solr/configsets/_default/conf/solrconfig.xml b/solr/server/solr/configsets/_default/conf/solrconfig.xml
index fd1d94c803f..f5ffe08b554 100644
--- a/solr/server/solr/configsets/_default/conf/solrconfig.xml
+++ b/solr/server/solr/configsets/_default/conf/solrconfig.xml
@@ -163,6 +163,15 @@
     <!-- <ramBufferSizeMB>100</ramBufferSizeMB> -->
     <!-- <maxBufferedDocs>1000</maxBufferedDocs> -->
 
+    <!-- Expert: ramPerThreadHardLimitMB sets the maximum amount of RAM that can be consumed
+         per thread before they are flushed. When limit is exceeded, this triggers a forced
+         flush even if ramBufferSizeMB has not been exceeded.
+         This is a safety limit to prevent Lucene's DocumentsWriterPerThread from address space
+         exhaustion due to its internal 32 bit signed integer based memory addressing.
+         The specified value should be greater than 0 and less than 2048MB. When not specified,
+         Solr uses Lucene's default value 1945. -->
+    <!-- <ramPerThreadHardLimitMB>1945</ramPerThreadHardLimitMB> -->
+
     <!-- Expert: Merge Policy
          The Merge Policy in Lucene controls how merging of segments is done.
          The default since Solr/Lucene 3.3 is TieredMergePolicy.
diff --git a/solr/server/solr/configsets/sample_techproducts_configs/conf/solrconfig.xml b/solr/server/solr/configsets/sample_techproducts_configs/conf/solrconfig.xml
index 8a48bb4d5ec..177bcd74e3a 100644
--- a/solr/server/solr/configsets/sample_techproducts_configs/conf/solrconfig.xml
+++ b/solr/server/solr/configsets/sample_techproducts_configs/conf/solrconfig.xml
@@ -165,6 +165,15 @@
     <!-- <ramBufferSizeMB>100</ramBufferSizeMB> -->
     <!-- <maxBufferedDocs>1000</maxBufferedDocs> -->
 
+    <!-- Expert: ramPerThreadHardLimitMB sets the maximum amount of RAM that can be consumed
+         per thread before they are flushed. When limit is exceeded, this triggers a forced
+         flush even if ramBufferSizeMB has not been exceeded.
+         This is a safety limit to prevent Lucene's DocumentsWriterPerThread from address space
+         exhaustion due to its internal 32 bit signed integer based memory addressing.
+         The specified value should be greater than 0 and less than 2048MB. When not specified,
+         Solr uses Lucene's default value 1945. -->
+    <!-- <ramPerThreadHardLimitMB>1945</ramPerThreadHardLimitMB> -->
+
     <!-- Expert: Merge Policy
          The Merge Policy in Lucene controls how merging of segments is done.
          The default since Solr/Lucene 3.3 is TieredMergePolicy.
diff --git a/solr/solr-ref-guide/src/indexconfig-in-solrconfig.adoc b/solr/solr-ref-guide/src/indexconfig-in-solrconfig.adoc
index 2318865ea66..39e87b942e1 100644
--- a/solr/solr-ref-guide/src/indexconfig-in-solrconfig.adoc
+++ b/solr/solr-ref-guide/src/indexconfig-in-solrconfig.adoc
@@ -56,6 +56,17 @@ Controls whether newly written (and not yet merged) index segments should use th
 <useCompoundFile>false</useCompoundFile>
 ----
 
+=== ramPerThreadHardLimitMB
+
+Sets the maximum memory (defined in megabytes) consumption per thread triggering a forced flush if exceeded. The given value must be greater than 0 and less than 2GB (2048 MB).
+
+[source,xml]
+----
+<ramPerThreadHardLimitMB>1945</ramPerThreadHardLimitMB>
+----
+
+NOTE: This is an expert level parameter as it triggers forced flush even if <<ramBufferSizeMB>> has not been exceeded.
+
 == Merging Index Segments
 
 === mergePolicyFactory
diff --git a/solr/test-framework/src/java/org/apache/solr/SolrTestCaseJ4.java b/solr/test-framework/src/java/org/apache/solr/SolrTestCaseJ4.java
index cc552920fe0..f717223282c 100644
--- a/solr/test-framework/src/java/org/apache/solr/SolrTestCaseJ4.java
+++ b/solr/test-framework/src/java/org/apache/solr/SolrTestCaseJ4.java
@@ -557,6 +557,7 @@ public abstract class SolrTestCaseJ4 extends SolrTestCase {
     System.setProperty("useCompoundFile", String.valueOf(iwc.getUseCompoundFile()));
 
     System.setProperty("solr.tests.maxBufferedDocs", String.valueOf(iwc.getMaxBufferedDocs()));
+    System.setProperty("solr.tests.ramPerThreadHardLimitMB", String.valueOf(iwc.getRAMPerThreadHardLimitMB()));
     System.setProperty("solr.tests.ramBufferSizeMB", String.valueOf(iwc.getRAMBufferSizeMB()));
 
     String mergeSchedulerClass = iwc.getMergeScheduler().getClass().getName();