diff --git a/core/src/main/scala/org/apache/spark/storage/DiskStore.scala b/core/src/main/scala/org/apache/spark/storage/DiskStore.scala
index 8dadf6794039e725ce674ef5511fa541cbb217bb..61ef5ff168791ed615c67aeb88ea79c100b84548 100644
--- a/core/src/main/scala/org/apache/spark/storage/DiskStore.scala
+++ b/core/src/main/scala/org/apache/spark/storage/DiskStore.scala
@@ -31,7 +31,8 @@ import org.apache.spark.util.Utils
 private[spark] class DiskStore(blockManager: BlockManager, diskManager: DiskBlockManager)
   extends BlockStore(blockManager) with Logging {
 
-  val minMemoryMapBytes = blockManager.conf.getLong("spark.storage.memoryMapThreshold", 2 * 4096L)
+  val minMemoryMapBytes = blockManager.conf.getLong(
+    "spark.storage.memoryMapThreshold", 2 * 1024L * 1024L)
 
   override def getSize(blockId: BlockId): Long = {
     diskManager.getFile(blockId.name).length
diff --git a/docs/configuration.md b/docs/configuration.md
index 2add48569beced0a452055c053a9325d9768198a..f292bfbb7dcd65c4ea9799d34e29499e0928e92c 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -678,7 +678,7 @@ Apart from these, the following properties are also available, and may be useful
 </tr>
 <tr>
   <td><code>spark.storage.memoryMapThreshold</code></td>
-  <td>8192</td>
+  <td>2097152</td>
   <td>
     Size of a block, in bytes, above which Spark memory maps when reading a block from disk.
     This prevents Spark from memory mapping very small blocks. In general, memory