Weblogic Server has a built-in feature for detecing ,avoding and recovering from overload conditions. So when a Weblogic server is experiencing Out of memory conditions or any of the Server Sub System is in failed state , we can instruct weblogic server to take corrective actions . We can tune the Weblogic server to take corrective actions during these overload states. We can for example instruct to kill the server process during a failed or a overload state so that the node manager or administrator can take corrective actions.
A managed-server can fail as a result of out-of-memory exceptions or stuck application threads, or if one of its services is running into an error condition. A managed-server instance can monitor its health. If it detects that an unstable state is reached, it declares itself failed.
By usiong the Weblogic Over load protection feature we can prevent the negative consequences like degraded application performance and stability causing the server not to take any requests from users.
Configuring the Over load protection
Go to Server -> Overload tab to configure the over load protection for that server.
In the overload tab we can see 2 actions which can taken when we see a Over load condition
Panic action - When the kernel encounters a panic condition , the below actions can be taken.The following two actions are available.
Exit the server process
When the server health monitoring encounters a critical situation and flags the server as failed, one of three predefined actions can be taken automatically
"Force immediate shutdown of this server", meaning that server will shut down completely
"Suspend server for correction action", meaning that server will go into admin state
There are certain other conditions that can be used that exists in the same tab ,
Max Stuck Thread Time - The number of seconds that a thread must be continually working before this server diagnoses the thread as being stuck
Stuck Thread Count - The number of stuck threads after which the server is transitioned into FAILED state. There are options in OverloadProtectionMBean to suspend and shutdown a FAILED server. By default, the server continues to run in FAILED state.
Hope this helps about the over load protection in weblogic.