It is rightfully said that the websphere application server is considered to be one of the market-leader application server which is commonly used for Java applications. Besides that IBM has started an WebSphere product line and is the base runtime element for various IBM products. Now these products can simply range from the mobile servers like IBM Worklight Server, Operational Decision Management Servers like WebSphere ILOG JRules, Integration servers like WebSphere Enterprise Service Bus and the list goes on.
As these products have the same runtime, the recommendation and tuning tips are the same to an extent.
When Do You Have To Tune Performance?
It is important that the performance tuning has to happen quite early in the project. Also, certain amount of time must be just allocated for factors like stress and load testing. Here the load testing simply means testing the normal app load with regard to the type of requests and expected concurrent request.
Now the stress testing consist of testing outside the required load level and consist of testing through an extended period of time, like for 6 to 8 hours. Keep in mind that during the duration of such test, the goal is simply to measure as well as monitor the performance of the application and the vital behaviour of the servers.
Websphere Applicaion Server Issues
● Failure of Application Server But startServer.log File Is Developed
Here the possible reason on why the problem occurs might be because the Java is corrupted. Also sometimes the issue can be due to the invalid JVM arguments that are often set on the JVM’s application server. Another reason might be due to the crashing of the startServer launcher or the corrupt sequence present in the Javasharedcache.
Sometimes for certain users, it might be due to the java.lang.UnsatisfiedLinkError and also because of the non-root user issues that is caused due to permission issue.
To solve this issue, you can simply try to run the command ‘java-fullversion’ from the WAS HOME/java/jre/bin directory. Sometimes there are chances for this particular command to fail, in such case, the Java can lead to issues. Also, sometimes when the server is initiated, there are chances of seeing the messages like “The System is Unable To Find The Specific Path” or “No Public JRE found”.
● Setting Up of Invalid JVM Arguments On The JVM Application Server
Here the major reason for the error to rise is because of the specified Java arguments that are used for the application server JVM because of the requirement of the application or any of the requirements of the stack product. Also another major reason for the issue might be due to the required Java arguments that are applicable to the application server JVM because of the requirement of the application or the presences of the stack product needs.
One method is to check out the maximum and minimum heap size values which are always set. Another solution is view or check out the server.xml file of the application server and find out if there are any kinds of specified JVM arguments which are invalid. Suppose if there is an invalid argument, then it is better if you try to remove it and check out when the server begins. Now if the server begins, then it is the major problem with any of the existing JVM properties.
● Corruption Of Java Class Cache
Sometimes there could be a possibility that the server’s Java cache can be corrupted. Here you need to keep in mind that the class cache is nothing but the area containing the shared memory which is of fixed size and also which can be persisti ng simply above the JVM’s lifetime. In addition, the JVM don’t have the cache and also there is no slave or master JVM concept. Rather than that here, any number of the JVM can write as well as read to the concurrent cache.
Now you need to run the command WAS_HOME\profiles\profile_name\bin>clearClassCache.bat/sh command to just clear and remove the Java cache of the current issue of the WebSphere Application Server. But keep in mind that if you are deleting the Java cache right from the system level it will just delete the cache of the each instance of the Java.
No doubt, the troubleshooting performance issues can be even time consuming and tedious. The above procedures can provide a certain details on some of them and how to avoid them.