tomcat+memcached集群后session丢失

[奔足包白勺虫呙牛]

tomcat集群，用memcached做缓存服务器，
系统正常启动，但session的生命周期只有10秒左右
十几秒后session丢失

ps：如果一直刷新浏览器激活可能会延长



context.xml配置如下：
<Manager className="de.javakaffee.web.msm.MemcachedBackupSessionManager"
memcachedNodes="n1:192.168.30.29:11211,n2:192.168.30.29:11212"
failoverNodes="n1" requestUriIgnorePattern=".*\.(png|gif|jpg|css|js)$"
sessionBackupAsync="false" sessionBackupTimeout="100"
transcoderFactoryClass="de.javakaffee.web.msm.serializer.javolution.JavolutionTranscoderFactory"
copyCollectionsForSerialization="false" />


求大神围观