tomcat+memcached，但seesion 共享不成功的问题

tomcat+memcached2台服务器分别运行2个tomcat，前端nginx负载，memcached安装后tomcat配在文件如下，但seesion 共享不成功
tomcat配置文件

<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
-->
<Manager className="de.javakaffee.web.msm.MemcachedBackupSessionManager"
            memcachedNodes="n1:192.168.1.126:11211"
            requestUriIgnorePattern=".*\.(png|gif|jpg|css|js)$"
            sessionBackupAsync="false"
            sessionBackupTimeout="100"
            transcoderFactoryClass="de.javakaffee.web.msm.serializer.javolution.JavolutionTranscoderFactory"
            copyCollectionsForSerialization="false" />
      <!-- Use the LockOutRealm to prevent attempts to guess user passwords
           via a brute-force attack -->

[root@user2 bin]# memcached -d -m 256 -p 11211 -u root -l 192.168.1.126 -v
failed to listen on TCP port 11211: Address already in use
这算是报错么？