After the installation of WebLogic Server 12c we have got cluster replication problems in our application test environment.

Although the same configuration used to work with Weblogic Server 10.3 now the secondary server seems to be removed and added to the cluster randomly.

<[ACTIVE] Execute '3' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <1332511394471> <BEA-000113> <Removing WL12c_ManagedServer_2 jvmid:4384922070744243395S:172.22.250.219:[10002,10002,-1,-1,-1,-1,-1]:project_domain:WL12c_ManagedServer_2 from cluster view due to PeerGone.>

<WL12c_ManagedServer_1> <weblogic.cluster.MessageReceiver> <<WLS Kernel>> <1332511403456> <BEA-003107> <Lost 2 unicast message(s).>

<WL12c_ManagedServer_1> <[ACTIVE] Execute '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <1332511403457> <BEA-002936> <maximum thread constraint weblogic.unicast.ForwardingWorkManager is reached>

<WL12c_ManagedServer_1> <[ACTIVE] Execute '3' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <1332511403460> <BEA-000111> <Adding WL12c_ManagedServer_2 with ID 4384922070744243395S:172.22.250.219:[10002,10002,-1,-1,-1,-1,-1]:project_domain:WL12c_ManagedServer_2 to cluster: ClusterWL12c view.>

<WL12c_ManagedServer_1> <[STANDBY] Execute '8' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <1332511403462> <BEA-000128> <Updating 4384922070744243395S:172.22.250.219:[10002,10002,-1,-1,-1,-1,-1]:project_domain:WL12c_ManagedServer_2 in the cluster.>

<WL12c_ManagedServer_1> <Execute '0' for queue: 'weblogic.socket.Muxer'> <<WLS Kernel>> <1332511413393> <BEA-002936> <maximum thread constraint weblogic.unicast.DispatchWorkManager is reached>

Further I see in the HttpClusterServlet log file that the secondary server hash is occasionally set to !NONE!

Environment Details (all servers are running on one physical server):

- 1 Node Server

- 1 Cluster (unicast) with 2 managed servers

- 1 Standalone managed server used as proxy (load balancer) based on HttpClusterServlet.

- Linux redhat 2.6.18-128

- Applications have been compiled using the weblogic server JDK

Part of config.xml:

<server>

<name>AdminServer</name>

<listen-port>17001</listen-port>

<listen-address></listen-address>

</server>

<server>

<name>WL12c_ManagedServer_1</name>

<ssl>

<enabled>false</enabled>

</ssl>

<machine>WL12c_Machine</machine>

<listen-port>10001</listen-port>

<cluster>ClusterWL12c</cluster>

<listen-address></listen-address>

<server-start>

<arguments>-Djava.awt.headless=true</arguments>

</server-start>

<jta-migratable-target>

<name>WL12c_ManagedServer_1</name>

<user-preferred-server>WL12c_ManagedServer_1</user-preferred-server>

<cluster>ClusterWL12c</cluster>

</jta-migratable-target>

<weblogic-plugin-enabled>false</weblogic-plugin-enabled>

</server>

<server>

<name>WL12c_ManagedServer_2</name>

<ssl>

<enabled>false</enabled>

</ssl>

<machine>WL12c_Machine</machine>

<listen-port>10002</listen-port>

<cluster>ClusterWL12c</cluster>

<listen-address></listen-address>

<server-start>

<arguments>-Djava.awt.headless=true</arguments>

</server-start>

<jta-migratable-target>

<name>WL12c_ManagedServer_2</name>

<user-preferred-server>WL12c_ManagedServer_2</user-preferred-server>

<cluster>ClusterWL12c</cluster>

</jta-migratable-target>

<weblogic-plugin-enabled>false</weblogic-plugin-enabled>

</server>

<server>

<name>WL12c_ProxyServer</name>

<ssl>

<enabled>false</enabled>

</ssl>

<machine>WL12c_Machine</machine>

<listen-port>9001</listen-port>

<cluster xsi:nil="true"></cluster>

<web-server>

<web-server-log>

<number-of-files-limited>false</number-of-files-limited>

</web-server-log>

</web-server>

<listen-address></listen-address>

</server>

<cluster>

<name>ClusterWL12c</name>

<cluster-messaging-mode>unicast</cluster-messaging-mode>

<weblogic-plugin-enabled>false</weblogic-plugin-enabled>

<frontend-host>build-env.rtd</frontend-host>

<frontend-http-port>9001</frontend-http-port>

<number-of-servers-in-cluster-address>2</number-of-servers-in-cluster-address>

</cluster>

Does anyone have an idea how to solve this issue?