Tool - 1: Health Center

Tool - 1: Health Center Joseph Amrith Raj http://facebook.com/webspherelibrary

2 Tool - 1: Health Center Table of Contents WebSphere Application Server Troubleshooting... Error! Bookmark not defined. About Health Center... 3 Installing and configuring HC... 5 Step-1 : HC tool in ISA... 5 Step -2 : HC Agent... 6 Step-3 : HC configuration for WebSphere Application Server...7 Starting and using HC... 8 Viewing and analyzing the collected data... 12 Classes... 12 Environment... 12 Garbage collection... 13 I/O... 14 Locking... 15 Native Memory... 16 Profiling... 17 References... 19 About Author... 19 Connect With US... 20

3 Tool - 1: Health Center In the previous part of this series [here], we discussed how to install the IBM support assistant workbench [ISA]. ISA is complementary software offering which provides you with a workbench to help you with problem determination. With a focus on quickly finding key information, automating repetitive steps and arming you with a variety of serviceability tools, you ll be prepared for self-analysis and diagnosis of problems and faster time to resolution. About Health Center In this, we will discuss one of the diagnose tool available in ISA to analyze the problems. The tool is Health Center. Health Center is a very low overhead monitoring tool. It runs alongside an IBM Java application with a very small impact on the application's performance. Health Center monitors several application areas, using the information to provide recommendations and analysis that help you improve the performance and efficiency of your application. Health Center can save the data obtained from monitoring an application and load it again for analysis at a later date. Health Center provides visibility, monitoring and profiling in the following application areas: Performance Java method profiling: The Health Center uses a sampling method profiler to diagnose applications showing high CPU usage. It's low overhead which means there is no need to specify in advance which parts of the application to monitor; the Health Center simply monitors everything. It works without recompilation or byte code instrumentation and shows where the application is spending its time, by giving full call stack information for all sampled methods. Lock analysis: Synchronization can be a big performance bottleneck on multi- CPU systems. It is often difficult to identify a hot lock or assess the impact locking is having on your application. Health Center records all locking activity and identifies the objects with most contention. Health Center analyses this information, and uses it to provide guidance about whether synchronization is impacting performance Garbage collection: The performance of Garbage Collection (GC) affects the entire application. Tuning GC correctly can potentially deliver significant performance gains. Health Center identifies where garbage collection is causing performance problems and suggests more appropriate command line options. Memory usage The Health Center will identify if your application is using more memory than seems reasonable, or where memory leaks occur. It then suggests solutions to memory issues, as well as Java heap sizing guidance. System Environment

4 Tool - 1: Health Center Health Center uses an 'environment perspective' to provide details of the Java version, Java classpath, boot classpath, environment variables, and system properties. This is particularly useful for identifying problems on remote systems or systems where you do not control the configuration. If the Health Center detects mis-configured applications, it will provide recommendations on how to fix it. Java Class loading Health Center provides class loading information, showing exactly when a class has been loaded and whether it is cached or not. This helps you determine whether your application is being affected by excessive class loading. File input and output Health Center uses an 'I/O perspective' to monitor application input or output (I/O) tasks as they run. You can use this perspective to monitor how many and which files are open, and to help solve problems such as when the application fails to close files. Real Time Monitoring The WebSphere Real Time perspective (WRTP) helps you identify unusual or exceptional events that might occur when you run a WRT application. The trace information can be presented in various ways, including linear or logarithmic scales, and histograms. WRTP provides some pre-defined trace point views that are especially helpful. Object Allocations Health Center allows you to view the size, time and code location of an object allocation request that meets specific threshold criteria. Health Center [HC] is a client-server model tool. This means, you can run the server anywhere and then you install a client into your JVM and connect it to the server. For example, I ve the server side component installed on my local machine and the clients are installed to all the development websphere application server machine. Now I can connect to the server on my local machine and monitor any server.

5 Tool - 1: Health Center Installing and configuring HC Step-1 : HC tool in ISA Open the ISA tool Go to update Find new Here you can find product and tool add-ons. Go to tool add-ons Expand the JVM based tools section and select, IBM Monitoring and Diagnostic tools for Java Health Center

6 Tool - 1: Health Center Click Next, accept the license terms and install. You need to restart ISA before you can use HC. Step -2 : HC Agent With the above steps, the configurations on the server side component of the HC are complete. The next step is to configure the client/jvms. Download the required HC agent for your platform form here Extract the downloaded zip file. You ll see Now copy these 3 files to the appropriate directories of websphere JAVA. For Example, if your websphere application server java is installed in /opt/ibm/websphere/java.. then copy:

7 Tool - 1: Health Center 1. healthcenter.so/dll to /opt/ibm/websphere/java/jre/bin 2. healthcenter.properties to /opt/ibm/websphere/java/jre/lib 3. healthcenter.jar to /opt/ibm/websphere/java/jre/lib/ext Step-3 : HC configuration for WebSphere Application Server The next step is to configure websphere application server. First, check what version of the JAVA you are using In the administration console, go to servers server type websphere application servers server_name java and process management process definition java virtual machine generic JVM arguments and the following: On UNIX/Linux systems: For Java 5 SR9 and earlier or Java 6 SR4 and earlier, use: -agentlib:healthcenter -Xtrace:output=/tmp/perfmon.%p.out For Java 5 SR10 and later, or Java 6 SR5 and later, use: -Xhealthcenter On Windows: For Java 5 SR9 and earlier or Java 6 SR4 and earlier, use: -agentlib:healthcenter -Xtrace:output=C:\temp\perfmon.%p.out For Java 5 SR10 and later, or Java 6 SR5 and later, use: -Xhealthcenter Apply the change and restart the JVM. The setup is complete. The default port used by HC agent is 1972. However you can change this in JAVA_HOME/jre/lib/healthcenter.properties

8 Tool - 1: Health Center Starting and using HC HC is a tool available in ISA, means first we need to launch and then launch the HC tool. After launching the ISA, click on analyze the issues.

9 Tool - 1: Health Center Now you need enable an application for monitoring.

10 Tool - 1: Health Center The red box in above screenshot is for the details of the HC agent. The green box is for authentication details to connect to the HC agent. After you enter the details and click Next, it will display the JVMs which can be monitored. Select a JVM and click Finish.

11 Tool - 1: Health Center The above screenshot is with all the default configurations. However you can customize the amount of data collected using Monitored JVM data collection settings

12 Tool - 1: Health Center Viewing and analyzing the collected data There are 7 perspectives available in the HC to view the collected data. Classes This prespective will display the class loading over the time. The starting point is when the JVM is started. It also shows weather the class is loaded from the shared cache. Usage: Will be helpful to analyze the out of memory errors. When a class is loaded, it will not be released until the classloader which loaded it is garbage collected. The loaded classes will occupy the heap memory. So, if more classes are loaded than the classes the unloaded, it might lead to outofmemory errors. Environment This perspective shows system and configuration information about the monitored JVM. Also, Analysis and recommendations panel will help you understand, if any parameters can affect system performance, stability and serviceability. [red box in below screenshot]

13 Tool - 1: Health Center Garbage collection This perspective will show, heap usage graph, pause times graph and shows recommendations. Used heap memory graph shows the memory usage by the applications on that JVM. It shows the heap size and heap size after garbage collection. Pause times chart shows the affect of garbage collection [GC] cycles. When GC is running, all the application threads are stopped. Longer garbage collection pauses are often associated with better application throughput and are not a performance problem. Spending extra time in garbage collection can often lead to improved memory allocation and memory access times. The aim of garbage collection tuning is to have reduced pause times only if low response times are required.

14 Tool - 1: Health Center Object allocation tab [ blue box in above screenshot] will let you identify which code is allocating large objects. The table shows, the size of the object allocated, time of the allocation and the code which allocated the request. Usage: helps you identify memory leaks and tune the heap sizes. I/O This perspective provides information about I/O activities performed by the JVM, like file open events, file close events and details files that are currently open.

15 Tool - 1: Health Center Locking This perspective provides information in graph and table form that helps you understand any contention caused by locking.

16 Tool - 1: Health Center Native Memory Native memory is the memory provided to the Java process by the operating system. The memory is used for heap storage and other purposes. This perspective provides information about the native memory usage of the process and system.

17 Tool - 1: Health Center Profiling This perspective helps you understand the work performed by the applications. You can use method profiling to see the methods that consume the most resources.

18 Tool - 1: Health Center Method profile view [red box in screenshot], shows which methods are using most processing resource. Invocation paths [green box in screenshot], shows the method that called the highlighted method. Called methods [blue box in screenshot], shows where the highlighted method is doing work. Timeline [brown box in screenshot], shows when the methods are invoked.

19 Tool - 1: Health Center References Overview of health center - http://www.youtube.com/watch?v=5tcktcl0qxs Install ISA and HC - http://www.youtube.com/watch?v=6wje9u0jvek How to enable a java app for HC - http://www.youtube.com/watch?v=hdp0mj13nlq About ISA : http://websphereapplicationservernotes.wordpress.com/2012/03/15/websphere -application-server-troubleshooting-part-0-ibm-support-assistant/ About Author Joseph Amrith Raj is a technical consultant for multiple WebSphere products. He worked on various product consulting and support teams including WebSphere Application Server, WebSphere MQ, WebSphere Message Broker, Enterprise Service Bus and WebSphere Process Server. He has 7 years of experience in administration, troubleshooting, consulting and he has significant experience in architecture, strategy and leadership positions. He is IBM certified for WAS, WMQ, WPS, SOA and Cloud Computing.

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