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Tuning the eWAS heap size for TDWC

Technote (FAQ)


How can you tune the embedded WebSphere Application Server (eWAS) to address performance issues when using Tivoli Dynamic Workload Console (TDWC)? Are there tuneable parameters?


You are having issues with performance of the embedded WebSphere Application Server (eWAS), especially during massive object queries from TDWC, or during planner activity.


A typical error message that is seen in the SystemOut.log is an OutOfMemory message.

Change the maximumHeapSize for eWAS, then restart the WebSphere Application Server.

The change can be done in this file:


Edit the following line at the bottom of the server.xml file:

"verboseModeClass="false" verboseModeGarbageCollection="false" verboseModeJNI="false" initialHeapSize="256" maximumHeapSize="1024"

Change the maximumHeapSize, then restart the WebSphere Application Server.

If you install TWS v8.6 on a 64 bit platform, you can increase the heapsize to 2048.

If you install TWS v8.5.1 on a 64 bit platform, check the operating system. This release of TWS still uses a 32-bit version of eWAS for some platforms (for example AIX, HP, and Solaris). In this case, the suggestion is to set the maximum heapsize value to 1536.

Server.xml location by product version:

TWS v8.4: <TWSHome>/appserver/profiles/twsprofile/config/cells/DefaultNode/nodes/DefaultNode/servers/server1/server.xml

TWS 8.5x:

TWS 8.6:

The same considerations are valid for Tivoli Dymanic Workload Console (TDWC) and the z/OS connector, and not only for TWS.

Related information

Recommended JVM Maximum Heapsize

Product Alias/Synonym


Document information

More support for: IBM Workload Scheduler
Tivoli Dynamic Workload Console

Software version: 8.4, 8.5, 8.5.1, 8.6

Operating system(s): UNIX

Reference #: 1600220

Modified date: 06 April 2015

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