tool - 1: health center

Joseph Amrith Raj

http://facebook.com/webspherelibrary

Tool - 1: Health Center

2 Tool - 1: Health Center

Joseph’s WebSphere Library

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



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

http://websphereapplicationservernotes.wordpress.com/2012/03/15/websphere-application-server-troubleshooting-part-0-ibm-support-assistant/



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.



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



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:

http://publib.boulder.ibm.com/infocenter/realtime/v2r0/index.jsp?topic=%2Fcom.ibm.softrt.doc%2Fhealthcenter%2Fcom.ibm.java.diagnostics.healthcenter.gui%2Fdocs%2Finstallingagent.html



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



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.



Now you need enable an application for monitoring.



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.



The above screenshot is with all the default configurations. However you can customize the

amount of data collected using ‘Monitored JVM data collection settings’



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]



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.



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.



Locking This perspective provides information in graph and table form that helps you understand any

contention caused by locking.



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.



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.



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.



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.

http://www.youtube.com/watch?v=5Tcktcl0qxs

http://www.youtube.com/watch?v=6WjE9U0jvEk

http://www.youtube.com/watch?v=Hdp0mJ13NLQ





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