diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/BlockCacheFactory.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/BlockCacheFactory.java
index 6956d584d92a..2e1bd3794ac8 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/BlockCacheFactory.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/BlockCacheFactory.java
@@ -86,6 +86,7 @@ private BlockCacheFactory() {
   public static BlockCache createBlockCache(Configuration conf) {
     FirstLevelBlockCache l1Cache = createFirstLevelCache(conf);
     if (l1Cache == null) {
+      LOG.debug("Block cache creation failed due to unsuccessful L1 cache creation.");
       return null;
     }
     boolean useExternal = conf.getBoolean(EXTERNAL_BLOCKCACHE_KEY, EXTERNAL_BLOCKCACHE_DEFAULT);
@@ -109,6 +110,7 @@ public static BlockCache createBlockCache(Configuration conf) {
   private static FirstLevelBlockCache createFirstLevelCache(final Configuration c) {
     final long cacheSize = MemorySizeUtil.getOnHeapCacheSize(c);
     if (cacheSize < 0) {
+      LOG.debug("L1 cache creation failed due to negative cache size.");
       return null;
     }
     String policy = c.get(BLOCKCACHE_POLICY_KEY, BLOCKCACHE_POLICY_DEFAULT);
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/util/MemorySizeUtil.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/util/MemorySizeUtil.java
index bf014dfb5303..f6a8296b7eee 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/util/MemorySizeUtil.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/util/MemorySizeUtil.java
@@ -210,6 +210,8 @@ public static long getOnHeapCacheSize(final Configuration conf) {
     float cachePercentage = conf.getFloat(HConstants.HFILE_BLOCK_CACHE_SIZE_KEY,
       HConstants.HFILE_BLOCK_CACHE_SIZE_DEFAULT);
     if (cachePercentage <= 0.0001f) {
+      LOG.debug("On heap cache is disabled due to " + HConstants.HFILE_BLOCK_CACHE_SIZE_KEY
+        + " is set to " + cachePercentage + " <= 0.0001");
       return -1;
     }
     if (cachePercentage > 1.0) {
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestBlockCacheReporting.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestBlockCacheReporting.java
index cda6c3c13723..f70089848080 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestBlockCacheReporting.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestBlockCacheReporting.java
@@ -18,6 +18,7 @@
 package org.apache.hadoop.hbase.io.hfile;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
 import java.io.IOException;
@@ -97,6 +98,7 @@ public void testLruBlockCache() throws IOException {
     CacheConfig cc = new CacheConfig(this.conf);
     assertTrue(CacheConfig.DEFAULT_IN_MEMORY == cc.isInMemory());
     BlockCache blockCache = BlockCacheFactory.createBlockCache(this.conf);
+    assertNotNull("blockCache creation failed", blockCache);
     logPerBlock(blockCache);
     addDataAndHits(blockCache, 3);
     // The below has no asserts. It is just exercising toString and toJSON code.