Monday Jun 11, 2012

Exalogic Exachk - Exalogic Health Check Tool now available on My Oracle Support

This is a new tool for Exalogic which automates the process of determining whether an Exalogic system is in a healthy state.

Exachk is available via MOS Doc Id. 1449226.1

Check the Quick Start Guide (available in the MOS Doc. Id. mentioned above) for further informarion.

Information about the Exachk healtcheck tool for Exadata can be seen at MOS Doc Id. 1070954.1

Friday May 18, 2012

CONNECTION_REFUSED messages on load balancing in Weblogic with OHS or Apache

In the last months I have had to work on some issues related to load balancing. It is very important to understand how the layers interact between them and where specific settings must be done.

Some people gets upset with the fact that OHS/Apache do load balancing even to servers that are shutdown and may be losing transactions.

This document provides very good tips about how many Production critical issues can be resolved just by setting the appropriate values for some parameters.

Personally, I think that the DynamicServerList parameter (which is in fact the first one mentioned on the document linked above) is particularly important to understand. As can be seen at this documentation from Oracle:
In a clustered environment, a plug-in may dispatch requests to an unavailable WebLogic Server instance because the DynamicServerList is not current in all plug-in processes.
DynamicServerList=ON works with a single Apache server (httpd daemon process), but for more than one server, such as StartServers=5, the dynamic server list will not be updated across all httpd instances until they have all tried to contact a WebLogic Server instance. This is because they are separate processes. This delay in updating the dynamic server list could allow an Apache httpd process to contact a server that another httpd process has marked as dead. Only after such an attempt will the server list will be updated within the proxy. One possible solution if this is undesirable is to set the DynamicServerList to OFF.
In a non-clustered environment, a plug-in may lose the stickiness of a session created after restarting WebLogic Server instances, because some plug-in processes do not have the new JVMID of those restarted servers, and treat them as unknown JVMIDs.
To avoid these issues, upgrade to Apache 2.0.x and configure Apache to use the multi-threaded and single-process model, mpm_worker_module.

Also, this Oracle documentation provides inportant information about "Failover, Cookies, and HTTP Sessions", and "Tuning to Reduce Connection_Refused Errors".

As can be seen at this Apache document, the MaxRequestsPerChild directive sets the limit on the number of requests that an individual child server will handle during its life.

Note that mod_proxy and related modules implement a proxy/gateway for Apache HTTP Server, supporting a number of popular protocols as well as several different load balancing algorithms. Third-party modules can add support for additional protocols and load balancing algorithms.

On Oracle Forums I also found a very interesting thread:
The error which you are getting is a common which can be fixed by increasing the "AcceptBackLog" value by 25% until error disappears from weblogic console (Path: Servers => => Configuration tab=> Tuning sub-tab.) and setting the value to ON for "KeepAlive" in the httpd.conf which should take care of your issue.
Topic: Tuning Connection Backlog Buffering
Search for "KeepAliveEnabled":
Also here is a link which would be helpful to understand some common issue which occurs when using a plug-in and there are solutions:

May transactions be affected because of this?
Certainly yes, but it depends on how your application is developed. A good practice would be to create a bunch of transactions and track them to check if some are missed or not. This Transaction and redelivery in JMS article may be helpful.

Wednesday Apr 18, 2012

REP-0178 - "Reports Server cannot establish connection" Error Message

During this last week I saw an interesting thread in Oracle Forums about this error message, and wanted to share the findings that I got to answer in the forum thread:
REP-0178: Reports Server [server_name] cannot establish connection

This problem may occur when a wrong rwclient is picked. Perhaps the environment is not set appropriately before rwclient is called or the rwclient.bat/ in /bin is found and used, but it is only a template that upon install allowed to create the valid rwclient.bat/ in the /config/reports/bin (in fact when the instance was actually configured).

So you can try using the appropriate rwclient.bat/ as it calls rwclient.exe/rwclient after setting the environment. Either set in the PATH the directory /config/reports/bin before /bin or specify the full path to rwclient.bat/

Another possibility can be that the services were started as root and therefore some log files have been created with the user root. Hence there is no more write access to theses log files for the basic Oracle user (which is the owner of the installation):

If that's the case, then try to change the owner of the following log files to ORACLE user (which is the owner of the installation):
And then restart the report server and run again the command to generate the reports.

Monday Mar 05, 2012

Exalogic Elastic Cloud Software Version 2.0 Released

The Oracle Engineered Systems Community is pleased to announce the availability of Exalogic Elastic Cloud Software (EECS) version 2.0, offering the following new features and enhancements:
  • A Layer 7 application traffic management software component called Oracle Traffic Director, which features extremely high performance HTTP load balancing (reverse proxy), HTTPS termination via Intel AES cryptography support, load balancing, rate throttling, connection limiting, logging and other advanced features
  • Support for secure application isolation using InfiniBand Partitions, a technology that allows the implementation of virtual firewalls on Exalogic in combination with Oracle Traffic Director
  • Improved Exabus implementation - which greatly improves system performance and provides new optimized integration with Oracle Coherence and Oracle Tuxedo, as well as performance enhancements for WebLogic Server and all other Oracle Linux and Solaris applications

  • As of February 16, 2012 all new Exalogic X2-2 configurations are being shipped with the EECS 2.0 firmware, device drivers, operating system images and utilities loaded on shared storage. Customers running existing Exalogic X2-2 systems at any previous EECS patch level will also be able to update their systems to EECS 2.0 via an upgrade kit expected to be released shortly.

Tuesday Jan 17, 2012

Exalogic Disaster Recovery White Paper

Lately there have been a lot of questions and requests around Disaster Recovery for Exalogic.
So it's good to keep in mind this link to the Disaster Recovery White Paper for Oracle Exalogic Elastic Cloud, which was published a couple of months ago.

Wednesday Dec 14, 2011

WebLogic Server 12c

WebLogic Server 12c has been released!

It is now certified for the full Java EE 6 platform specification, which enables higher developer productivity with standards-based, modern APIs, including Servlet 3.0, JAX-RS 1.1, Java Server Faces 2.1, EJB 3.1, Context and Dependency Injection for Java, and many others.

It also adds support for reading and using GlassFish's web deployment descriptors. This is useful for providing specific GlassFish behavioral settings and mappings for resources and security to WebLogic Server.

Tuesday Nov 15, 2011

Exalogic: Ready for the Future

Monday Oct 24, 2011

ExalogicTV Channel on YouTube

We now have a public YouTube channel hosting a series of videos around Exalogic. This is a living project and more videos will continue being added. If you subscribe to the channel you will get email updates as new videos are posted automatically. There are currently 13 Exalogic videos live.


Wednesday Oct 12, 2011

Focus on Oracle Exalogic Elastic Cloud at Oracle OpenWorld 2011

In the upcoming Oracle OpenWorld there will be several sessions and events that would be of interest to anyone who wants to learn more about the Oracle Exalogic Elastic Cloud. There are many excellent presenters, a ton of new data, fantastic new demos and numerous opportunities to hear about Exalogic directly from Exalogic customers.

For further information, take a look at

Friday Sep 23, 2011

Coherence 3.7.1 Released

Coherence 3.7.1 is now available on OTN.

This new release of Coherence provides major enhancements for Exalogic and contains many new exciting features:
- REST Support
- Exabus Support
- Query Explain Plan
- Elastic Data Improvements
- Pluggable Partitioning
- REST interface
- POF Improvements
- Eliminate need for Java Key Classes

Thursday Sep 01, 2011

The MANIFEST.MF filename... Oh My!

In the last month I worked a Service Request along with my colleague Ernani Mattos, where on WebLogic 10.3.4, when attempting to deploy Coherance*Web, the following error occurs on RedHat, but not on Windows or Debian:
weblogic.application.ModuleException: Missing Coherence jar or WebLogic Coherence Integration jar

The customer was following the Caching Sessions with Coherence and WebLogic Server documentation.

Taking a look at the ModuleException, the coherence.jar is part of the counter.war application, and the Weblogic.coherence.integration.jar is declared with the active-cache-1.0.jar lib which is referenced by the MANIFEST.MF of the counter application.

The entire issue was that MANIFEST.MF on the counter.war was named as ""; Therefore RedHat Linux could not recognize it simply due to the naming issues. So make sure that manifest file name is "MANIFEST.MF" and declares to active-cache-1.0.jar which should be deployed as a lib on the servers.

This was solved by executing the following steps:
1. Explode the counter.war application
2. Goto counter/META-INF/ directory
3. Rename the to MANIFEST.MF
4. Deploy as open directory or compact back to war file and deploy

Monday Aug 08, 2011

Error " Address already in use: JVM_Bind" when running Node Manager in Windows

After a brand new install of WebLogic Server, when accessing node manager the following error is thrown:
GRAVE: Fatal error in node manager server Address already in use: JVM_Bind at Method) at at at Source) at at at at Source) at Source) at weblogic.nodemanager.server.SSLListener.init( at weblogic.nodemanager.server.NMServer.start( at weblogic.nodemanager.server.NMServer.main( at weblogic.NodeManager.main(

When WebLogic is installed in Windows, the NodeManager is set as a Windows service which is automatically started up and runs on port 5556 (default).

The node manager is already started. It can be shut down in the windows services, and to avoid that it is started up automatically along with Windows, the startup type can be changed.

Monday Jul 25, 2011

WLST on web

My colleague Antonio De Juan, who is a partner of mine in the Chilean office of Oracle, has created a really innovative application named wlstonweb, which allows to have interactive WLST Sessions and WLST Script Management both via a web browser.

The tool can be accessed here.

About the tool Creator: Antonio De Juan
Antonio has been part of the Middleware - Application Server Team, supporting WebLogic Server for almost two years and he has recently joined to Coherence Support as second product too.

Tuesday Jul 19, 2011

Using WebLogic Server to Simply Store Static Content

A couple of weeks ago I saw a forum thread which I found very interesting. A guy was asking if it's possible or not to use WebLogic as a Web Server, in a similar way than when an index.html file is placed on the 'www' directory of Apache. So I answered him.

Actually you can use WebLogic as a web server, but unlike Apache where you place a html file to the www directory and you can see it immediately, in WebLogic you have to deploy it to a domain.

1. The html files (or any other static content like pdf files) must be in a directory of your choice (i.e. C:\testhtml).

2. On that directory create a WEB-INF directory (from the example of step 1 it would be C:\testhtml\WEB-INF).

3. In the WEB-INF directory create a file called web.xml with the following content:
<?xml version="1.0" encoding="UTF-8"?>
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"

4. Login to the WebLogic Console to deploy the application (i.e. http://[your_server]:7001/console )

5. Click on Deployments.

6. Click Install and set the path to the directory of step 3 (if the directory only contains the html file and the WEB-INF subdirectory you will see no files to select, but the Next button will be enabled anyway).

7. Leave default "Install this deployment as an application" and click Next.

8. Select the servers you wish to deploy this.

9. Accept the defaults and click Finish.

10. Activate Changes if the message appears.

11. You should now be able to see the application started in the deployments screen.

12. You can now access your static content on the WebLogic Server port via the following URL: http://[your_server]:7001/testhtml/[your_static_file]

Wednesday Jun 22, 2011

Bay Area Coherence Special Interest Group Next Meeting July 21, 2011

Date: Thursday, July 21, 2011
Time: 4:30pm - 8:15pm ET (note that Parking at 475 Sansome Closes at 8:30pm)
Where: Oracle Office, 475 Sansome Street, San Francisco, CA Google Map

We will be providing snacks and beverages.

Register! - Registration is required for building security.

Presentation Line Up:

5:10pm - Batch Processing Using Coherence in Oracle Group Policy Administration - Paul Cleary, Oracle
Oracle Insurance Policy Administration (OIPA) is a flexible, rules-based policy administration solution that provides full record keeping for all policy lifecycle transactions. One component of OIPA is Cycle processing, which is the batch processing of pending insurance transactions. This presentation introduces OIPA and Cycle processing, describing the unique challenges of processing a high volume of transactions within strict time windows. It then reviews how OIPA uses Oracle Coherence and the Processing Pattern to meet these challenges, describing implementation specifics that highlight the simplicity and robustness of the Processing Pattern.

6:10pm - Secure, Optimize, and Load Balance Coherence with F5 - Chris Akker, F5
F5 Networks, Inc., the global leader in Application Delivery Networking, helps the world’s largest enterprises and service providers realize the full value of virtualization, cloud computing, and on-demand IT. Recently, F5 and Oracle partnered to deliver a novel solution that integrates Oracle Coherence 3.7 with F5 BIG-IP Local Traffic Manager (LTM). This session will introduce F5 and how you can leverage BIG-IP LTM to secure, optimize, and load balance application traffic generated from Coherence*Extend clients across any number of servers in a cluster and to hardware-accelerate CPU-intensive SSL encryption.

7:10pm - Using Oracle Coherence to Enable Database Partitioning and DC Level Fault Tolerance - Alexei Ragozin, Independent Consultant and Brian Oliver, Oracle
Partitioning is a very powerful technique for scaling database centric applications. One tricky part of partitioned architecture is routing of requests to the right database. The routing layer (routing table) should know the right database instance for each attribute which may be used for routing (e.g. account id, login, email, etc): it should be fast, it should fault tolerant and it should scale. All the above makes Oracle Coherence a natural choice for implementing such routing tables in partitioned architectures. This presentation will cover synchronization of the grid with multiple databases, conflict resolution, cross cluster replication and other aspects related to implementing robust partitioned architecture.

Additional Info:

- Download Past Presentations: The presentations from the previous meetings of the BACSIG are available for download here. Click on the presentation titles to download the PDF files.

- Join the Coherence online community on our Oracle Coherence Users Group on LinkedIn.

- Contact BACSIG with any comments, questions, presentation proposals and content suggestions.

Principal Technical Support Engineer in the Exalogic Enterprise Support Team (EEST).


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