weblogic.xml会话复制区别?

# memory—Disables persistent session storage.
# replicated—Same as memory, but session data is replicated across the clustered servers.
# replicated_if_clustered—If the Web application is deployed on a clustered server, the in-effect persistent-store-type will be replicated. Otherwise, memory is the default.
# sync-replication-across-cluster—The replication will occur synchronously across the cluster.
# async-replication-across-cluster—The replication will occur asynchronously across the cluster.

请详细解释什么时候使用replicated和sync-replication-across-cluster以及这两个的区别？

没人回答自己回答哈哈！
firstly ,you should understand that these configurations is for CLUSTER of many machines(except #memory,cause one machine can use shared memory to share the session).
# memory
as you can see,it means use memory to store the session state.only the primary server which creates the session will keep the session.
#replicated
different servers in one cluster to keep the same state of one user session.

# sync-replication-across-cluster
# async-replication-across-cluster

for this two,please be aware of ACROSS-CLUSTER. it's used when you have several clusters!