diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index e240da9eb3c..4f916ad0db6 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -231,6 +231,8 @@ Other Changes
 * SOLR-5213: Log when shard splitting unexpectedly leads to documents going to
   no or multiple shards (Christine Poerschke, Ramkumar Aiyengar)
 
+* SOLR-7425: Improve MDC based logging format. (Mark Miller)
+
 ==================  5.1.0 ==================
 
 Consult the LUCENE_CHANGES.txt file for additional, low level, changes in this release
diff --git a/solr/core/src/java/org/apache/solr/util/SolrLogLayout.java b/solr/core/src/java/org/apache/solr/util/SolrLogLayout.java
index 71d4ffc429e..31ba8bcb0ed 100644
--- a/solr/core/src/java/org/apache/solr/util/SolrLogLayout.java
+++ b/solr/core/src/java/org/apache/solr/util/SolrLogLayout.java
@@ -365,19 +365,19 @@ public class SolrLogLayout extends Layout {
 
   private void appendMDC(StringBuilder sb) {
     if (!StringUtils.isEmpty(MDC.get(NODE_NAME_PROP)))  {
-      sb.append(" N:").append(MDC.get(NODE_NAME_PROP));
+      sb.append(" n:").append(MDC.get(NODE_NAME_PROP));
     }
     if (!StringUtils.isEmpty(MDC.get(COLLECTION_PROP)))  {
-      sb.append(" C:").append(MDC.get(COLLECTION_PROP));
+      sb.append(" c:").append(MDC.get(COLLECTION_PROP));
     }
     if (!StringUtils.isEmpty(MDC.get(SHARD_ID_PROP))) {
-      sb.append(" S:").append(MDC.get(SHARD_ID_PROP));
+      sb.append(" s:").append(MDC.get(SHARD_ID_PROP));
     }
     if (!StringUtils.isEmpty(MDC.get(REPLICA_PROP))) {
-      sb.append(" R:").append(MDC.get(REPLICA_PROP));
+      sb.append(" r:").append(MDC.get(REPLICA_PROP));
     }
     if (!StringUtils.isEmpty(MDC.get(CORE_NAME_PROP))) {
-      sb.append(" c:").append(MDC.get(CORE_NAME_PROP));
+      sb.append(" x:").append(MDC.get(CORE_NAME_PROP));
     }
   }
 }