11) How to deploy web/jar files in Weblogic or tomcat in unix/Linux environment ?
A) In weblogic 9.0--> 1)copy the web / Jar Application paste in Auto deployment folder.it's called Hot deployment.
2) Otherwise go to Administrative console--> http://localhost:7001/console --> Deployment->Loc/Edit Click--> Install--> select source path3) WLST --> Weblogic Scripting tool--> type command Deploy
java.Weblogic.Deployer http://localhost:7001 -user weblogic -password weblogic -deploy application name Managedserver1,Managed server2.
12) In which log file garbage collector information will be recorded ? how to enable garbage collector ?
A) ----> Nativestdout.log Nativestderr.log are GC logs
---> get into the admin console ->applicationserver->select JVM->Java & Process Management->process definition-> Java Virtual Machine.
There u will have an option to enable GC logging.
13) How can we check the performance of the application server without external monitoring tools?
A) Through Websphere in build monitoring tool called Tivoli Performance Monitoring under Monitoring and tuning in Admin Console.
(or)
Tivoli Performance Viewer (TPV): It enables the administrators and programmers to monitor the overall health of the WebSphere Application Server without leaving the Admin console.
From TPV, you can view current activity or log Performace Monitoring Infrastructure(PMI) for the following:
- System resources such as CPU utilization.
- WebSphere pools and queues such as DB connection pool.
- Customer Application data such as servlet response time.
14) Can someone explain what it means by Federate A NODE ?
A) ---> Federation is nothing but addition.
----> Federating the node means we have to add the node of the standalone application server to the DMGR profile.
(OR)
----> Federating node means adding stand alone application or stand alone profile to deployment manager(DMGR), we can achieve this by using admin console or addnode command of stand alone profile.
CMD: ./addNode.sh
----> Once this process is successfully done, one nodeagent server is created for app server, this nodeagent is responsible for communication between dmgr and application server.
A) ---> When I upload a big file through java application running on Websphere Application Server , I got OutOfMemoryError , as given below
----> JVMDUMP013I Processed Dump Event "uncaught", detail "java/lang/OutOfMemoryError".
----> Also memory leak is a common memory problem that also leads to OutOfMemory error. In Java , memory leaks can not happen as it has automatic Garbage Collection (GC). GC removes unused objects that are not referenced anymore. But if an object is not used, but is still referenced, GC does not remove it, which leads to memory leaks in JVM .
-----> Due to the above memory leak or large objects error , the performance of the application server may decline
----> WAS may be crashed with OutOfMemory error. please check the error message java.lang.OutOfMemoryError” in the WAS log file ( i.e. native_stderr.log)
----> One of Solution to the above error :
----> When I increase the JVM Heap Size , the problem got solved . Now let us see , how to increase JVM Heap Size in Websphere Application Server
-----> You can solve the problem in two ways
i) Using the IBM console
ii) By changing the server.index file directly
----> i). To tune the JVM Max Heap size using the IBM console
-----> 1. Open the WebSphere Application Server administrative console,
http://hostname:port/ibm/console, and log in.
2. Expand Servers -> Application servers -> server1 -> Java and Process Management -> Process Definition -> Java Virtual Machine.
3. Change the Max Heap Size to a larger value.
4. Click Apply and click Save .
Restart WebSphere Application Server.
-----> ii) By changing the server.xml file directly
Open the server.xml file located in the following directory
/opt/IBM/WebSphere/AppServer/profiles/AppSrv01/config/cells/YourSrverNode01Cell/nodes/YourServerNode01/servers/server1
----> Then you have to reduce the max heap size value using the IInd method ..(i.e. change server.xml file directly)
----> Tuning the max heap size
Setting the JVM heap size directly relates to the number of server instances need to be started on a specific node and the total RAM available on that machine. The total value of all server JVM heap sizes on a specific node must be less than half of the total RAM of that computer. To determine the max heap size , you can use the following equation
max_heap_size = Total_RAM / 2 / no_of_servers_instance
For example, to support two servers instance on a machine with 4 GB of RAM:
max_heap_size = 4 GB / 2 / 2
=2 GB / 2 = 1 GB
The maximum heap size is 1 GB for each server instance.
----> Default maximum heap size is 250 MB
------> Increasing the minimum heap size & maximum heap size can improve the start-up of application server. The number of garbage collection (GC) occurrences are reduced and a 10% gain in performance is realized.
16) How to determine Max Heap Size is too large or too small for your application.?
A) ----> If GC takes a so long time to clean up objects with large heap, you can reduce the maximum heap size.
-----> If GC frequency is too high, the heap may be too small for the application and GC needs to run frequently, so you may increase the maximum heap size.
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