diff --git a/akka-persistence/akka-persistence-common/src/main/scala/CommonStorageBackend.scala b/akka-persistence/akka-persistence-common/src/main/scala/CommonStorageBackend.scala
index 17502903f0..42e5fa8819 100644
--- a/akka-persistence/akka-persistence-common/src/main/scala/CommonStorageBackend.scala
+++ b/akka-persistence/akka-persistence-common/src/main/scala/CommonStorageBackend.scala
@@ -215,7 +215,7 @@ private[akka] object KVStorageBackend {
 
 private[akka] trait CommonStorageBackend extends MapStorageBackend[Array[Byte], Array[Byte]] with VectorStorageBackend[Array[Byte]] with RefStorageBackend[Array[Byte]] with QueueStorageBackend[Array[Byte]] with Logging {
   import CommonStorageBackend._
-  val mapKeysIndex = IntSerializer.toBytes(-1)
+  val mapKeysIndex:Array[Byte] = new Array[Byte](1).padTo(1,1.asInstanceOf[Byte])
   val vectorHeadIndex = IntSerializer.toBytes(-1)
   val vectorTailIndex = IntSerializer.toBytes(-2)
   val queueHeadIndex = IntSerializer.toBytes(-1)
diff --git a/akka-persistence/akka-persistence-memcached/src/main/scala/MemcachedStorageBackend.scala b/akka-persistence/akka-persistence-memcached/src/main/scala/MemcachedStorageBackend.scala
index 83e056900f..b84b99adbd 100644
--- a/akka-persistence/akka-persistence-memcached/src/main/scala/MemcachedStorageBackend.scala
+++ b/akka-persistence/akka-persistence-memcached/src/main/scala/MemcachedStorageBackend.scala
@@ -25,13 +25,13 @@ private[akka] object MemcachedStorageBackend extends CommonStorageBackend {
   val client = new MemcachedClient(factory, AddrUtil.getAddresses(clientAddresses))
   val base64 = new Base64(76, Array.empty[Byte], true)
 
-  def queueAccess = new MemcachedAccess("que")
+  def queueAccess = new MemcachedAccess("Q")
 
-  def mapAccess = new MemcachedAccess("map")
+  def mapAccess = new MemcachedAccess("M")
 
-  def vectorAccess = new MemcachedAccess("vec")
+  def vectorAccess = new MemcachedAccess("V")
 
-  def refAccess = new MemcachedAccess("ref")
+  def refAccess = new MemcachedAccess("R")
 
   private[akka] class MemcachedAccess(val accessType: String) extends KVStorageBackendAccess {