Weblogic Authors: Yeshim Deniz, Elizabeth White, Michael Meiner, Michael Bushong, Avi Rosenthal

Related Topics: Weblogic

Weblogic: Article

'HTTP Session Replication Failure' Issues

Moving away from the primary thought

Sometimes, HTTP session states are not replicated from the primary server to the secondary server.


  1. The application using HTTP session does not function as designed and you see a loss of session data.
  2. You might be asked to re-log into the application even when the session has still not timed out.
  3. You see errors and warnings related to HTTP session failures in the server's log file.
  4. The request is not failed over to another server properly.

There are several reasons as to why session replication fails. We will look at ways to diagnose the issue, possible reasons for it, and the ways to address them.

Types of HTTP Session Replication
There are five different implementations of session persistence:

  • Memory (single-server, non-replicated): When you use memory-based storage, all session information is stored in memory and is lost when you stop and restart WebLogic Server.
  • File system persistence: Session information is stored in a file under the PersistentStoreDir specified.
  • JDBC persistence: Session information is stored in a database table.
  • Cookie-based session persistence: Session information is stored in a cookie.
  • In-memory replication (across a cluster): Session data is copied from one server instance to another into memory.

Diagnosing the Issue
Consider a scenario with two servers (MyServer-1, MyServer-2) in a cluster. When you enable the debug flags (see the "Enable the Debug Flags to Track Session Replication Failures"section), you will see the messages below when a request from a client is sent the very first time.

On MyServer-1:

<Oct 9, 2003 12:38:21 PM PDT> <Debug> <Cluster> <000000>
<Creating primary 5165892837402719733>
<Oct 9, 2003 12:38:21 PM PDT> <Debug> <Cluster> <000000>
<Created secondary for 5165892837402719733 on -7957889153726652135S: [9001,9001, -1, -1,9001, -1, -1]: mydomain: MyServer-2>

This logging message means that the primary server is MyServer-1 and a secondary has been created on MyServer-2. A message like the one shown below will be logged on MyServer-2 to confirm that.

ExecuteThread: '1' for queue: 'Replication'> <kernel identity> <>
<000000> <Creating secondary 5165892837402719733>
####<Oct 9, 2003 12:38:21 PM PDT> <Debug> <Cluster>
<rvimala-c840> <MyServer-2> <ExecuteThread:
'1' for queue: 'Replication'>
<kernel identity> <> <000000>
<Updated local secondary of 5165892837402719733>

If you check the JSESSIONID it looks like:


JSESSIONID is the default name of the cookie, which could be changed to anything in weblogic.xml. The format of JSESSIONID is

SessionId!PrimaryServer JVM Hash!SecondaryServer JVMHash

Every time data is changed (either set/get or removed) in the session you'll see the logging message.

On MyServer-1:

<Oct 9, 2003 12:38:21 PM PDT> <Debug> <Cluster> <000000>
<Updated remote secondary for 5165892837402719733>

On MyServer-2:

####<Oct 9, 2003 12:38:21 PM PDT> <Debug> <Cluster>
<rvimala-c840> <MyServer-2> <ExecuteThread:
'1' for queue: 'Replication'> <kernel identity> <> <000000>
<Updated local secondary of 5165892837402719733>

If for any reason session replication fails, you will see the message below in the MyServer-1 log:

<Nov 6, 2003 12:59:12 PM EST> <Debug> <Cluster> <000000>
<Unable to create secondary for -5165892837402719733>
<Nov 6, 2003 12:59:12 PM EST> <Debug> <Cluster> <000000>
<Error creating secondary 5165892837402719733 on -7957889153726652135S:[9001,9001,-1,-1,9001,-1,-1]:mydomain:MyServer-2>

And, the JSESSIONID would appear as


The secondary server hash would become NONE

Enable the Debug Flags to Track Session Replication Failures
You can enable the flags DebugCluster, DebugClusterAnnouncements, DebugFailOver, DebugReplication, and DebugReplicationDetails.

To Enable
Use the weblogic.Admin command-line utility to dynamically turn the debug options on and off. For example, to turn on DebugCluster on all administration instances of ServerDebug MBean (i.e., Admin Server or al Managed Server):

java weblogic.Admin -url t3://localhost:7001 -username system -password weblogic
SET -type ServerDebug -property DebugCluster true

Or, edit the config.xml and the MBean element in the <ServerDebug/> stanza for each server that you want to debug and set it to a value of "true" to enable or "false" to disable. Then you must restart the Admin Server. Managed Servers will reconnect to the Admin Server and the debug flags will then dynamically take effect. For example:

<ServerDebug DebugCluster="true" Name="myserver"/>

At the end, with all the flags set, in your config.xml the ServerDebug tag would look like:

<ServerDebug ClassFinder="true" DebugCluster="true"
DebugClusterAnnouncements="true" DebugFailOver="true"
DebugReplication="true" DebugReplicationDetails="true" Name="MyServer1"/>

Make sure the stdOutSeverity level of the server is INFO and StdoutDebugEnabled is set to "true". The debug information will be logged into the server log as well as to the standard out.

Checklist for Each Session Persistence Type
Memory (Single Server, Nonreplicated)

  1. When you use memory-based storage, all session information is stored in memory and is lost when you stop and restart BEA WebLogic Server.
  2. Make sure you have allocated sufficient heap size when running WebLogic Server; otherwise, your server may run out of memory under heavy load.
  3. Not a recommended type for Cluster configuration (because the data is kept in heap and is not available to any other server).

File System Persistence

  1. Verify that the directory where BEA WebLogic Server stores the sessions is correctly specified in weblogic.xml. You must also create this directory yourself and make sure appropriate access privileges have been assigned to the directory.
  2. Make sure you have enough disk space.

JDBC Persistence
Make sure the connection pool that connects to the database has read/write access for the database table used.

Cookie-Based Persistence

  1. Make sure you have not stored anything other than java.lang.String in the HTTP session.
  2. Do not flush the HTTP response object in your application code.
  3. Make sure that the content length of the response exceeds the buffer size set (default is 8192 bytes).
  4. Make sure that cookies are enabled in the browser.
  5. Make sure that you do not use commas (,) in a string when using cookie-based session persistence.

In-Memory Replication

  1. Make sure that the BEA WebLogic Server is accessed only via a proxy server or a hardware load balancer
  2. The hardware load balancer should support a compatible passive or active cookie persistence mechanism, and SSL persistence.
  3. Recommended type in a cluster.

Validate the weblogic.xml Entries
Make sure weblogic.xml has all the parameters that need to be set for each Session Replication type. For example, when using in-memory replication the sample weblogic.xml would look like:

<session-descriptor> <session-param> <param-name> PersistentStoreType </param-name> <param-value> replicated </param-value> </session-param> </session-descriptor>

Note: The debug files are subjected to change with each version of BEA WebLogic Server.

Session Data Must Be Serializable
To support in-memory replication of HTTP session states, all servlet and JSP session data must be serializable or else session replication would fail.

When debugging is enabled, BEA WebLogic Server would output the warning messages below by indicating that the session is not replicated. After this, session replication would stop.

Debug Message:

<Oct 8, 2003 2:10:45 PM PDT> <Error> <Cluster> <000126>
<All session objects should be serializable to replicate.
Please check the objects in your session.
Failed to replicate non-serializable object>

On the subsequent request the JSESSIONID will be missing the secondary server and will be marked NONE, e.g.:


Solution: Find out the page the error is thrown from and make sure that all the data put into the session is serializable.

Check for Network/Multicast Issues
Make sure that the network is fine and there are no multicast issues. Do the multicast test to make sure that the multicast IP is working fine.


java utils.MulticastTest -n name -a address [-p portnumber] [-t timeout] [-s send]


Validate Cluster Configuration
The primary and secondary servers are selected from the cluster list. In a cluster of two servers, if the cluster doesn't have all the servers, then a secondary might not be chosen, resulting in the session data not being replicated.

To verify, execute the following commands:

  1. Make sure weblogic.jar is in the classpath.
  2. To get all the servers in a cluster:

java weblogic.Admin -username weblogic -password weblogic -url
http://oneofthemanagedserverurlinthecluster:7001/ GET -type ClusterRuntime -pretty

This will list all the servers in a cluster. The URL could be changed to every server in the cluster to make sure they all have the same entries.

Application Code Diagnostics
Make sure you use only setAttribute/removeAttribute methods of the HTTP session in your application code to update the HTTP session. If you use other set methods to change objects within a session, BEA WebLogic Server does not replicate those changes.

Please do not use the methods putValue and removeValue of the HTTP session as they are deprecated and there could be issues with session data replication when using such methods in your application. Instead, use only the setAttribute/removeAttribute methods of the Http session.

Cookies vs URL Rewriting
In some situations, a browser or wireless device may not accept cookies, which makes session tracking with cookies impossible. URL rewriting is a solution to this situation that can be substituted automatically when WebLogic Server detects that the browser does not accept cookies. Enable URL rewriting in BEA WebLogic Server by setting the URLRewritingEnabled attribute in the WebLogic-specific deployment descriptor, weblogic.xml, under the <session-param> element. The default value for this attribute is true.

Performance Issues

  • Consider serialization overhead: Serializing session data introduces some overhead for replicating the session state. The overhead increases as the size of the serialized objects grows. If you plan to create very large objects in the session, test the performance of your servlet to ensure that performance is acceptable.
  • Control frame access to session data: If you are designing a Web application that utilizes multiple frames, keep in mind that there is no synchronization of requests made by frames in a given frameset. For example, it is possible for multiple frames in a frameset to create multiple sessions on behalf of the client application, even though the client should logically create only a single session.

    To avoid unexpected application behavior, carefully plan how you access session data with frames. You can apply one of the following general rules to avoid common problems:
    - In a given frameset, ensure that only one frame creates and modifies session data.
    - Always create the session in a frame of the first frameset your application uses (for example, create the session in the first HTML page that is visited). After the session has been created, access the session data only in framesets other than the first frameset.

  • Storing larger amounts of data in the session: JDBC persistence and File persistence won't be faster as the session data has to be stored and retrieved from an external resource. There is also a performance overhead because of JDBC access for each session update. If you want to store large objects in the session, then JDBC or File persistence should be considered.
  • Storing small amount of data in the session: Cookie-based session persistence is most useful when you do not need to store large amounts of data in the session. Cookie-based session persistence can make managing your BEA WebLogic Server installation easier because clustering failover logic is not required.

    Further Information
    For additional information go to http://support.bea.com for some published solutions on session replication failures. You can also query ASK BEA at http://websupport.beasys.com/index.jsp.

    If none of these help you towards a solution or an identifier in your application, then contact BEA Customer Support for further diagnosis. You can open a case with a valid support contract by logging in at http://support.bea.com/login.jsp

  • More Stories By Vimala Ranganthan

    Vimala Ranganathan is a backline developer relations engineer with BEA Systems. She specializes in troubleshooting and solving complex customer issues with their mission-critical applications on BEA products. Vimala holds a bachelor's degree in computer science.

    Comments (0)

    Share your thoughts on this story.

    Add your comment
    You must be signed in to add a comment. Sign-in | Register

    In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.

    @ThingsExpo Stories
    Enterprises have taken advantage of IoT to achieve important revenue and cost advantages. What is less apparent is how incumbent enterprises operating at scale have, following success with IoT, built analytic, operations management and software development capabilities - ranging from autonomous vehicles to manageable robotics installations. They have embraced these capabilities as if they were Silicon Valley startups.
    The standardization of container runtimes and images has sparked the creation of an almost overwhelming number of new open source projects that build on and otherwise work with these specifications. Of course, there's Kubernetes, which orchestrates and manages collections of containers. It was one of the first and best-known examples of projects that make containers truly useful for production use. However, more recently, the container ecosystem has truly exploded. A service mesh like Istio addr...
    Predicting the future has never been more challenging - not because of the lack of data but because of the flood of ungoverned and risk laden information. Microsoft states that 2.5 exabytes of data are created every day. Expectations and reliance on data are being pushed to the limits, as demands around hybrid options continue to grow.
    Poor data quality and analytics drive down business value. In fact, Gartner estimated that the average financial impact of poor data quality on organizations is $9.7 million per year. But bad data is much more than a cost center. By eroding trust in information, analytics and the business decisions based on these, it is a serious impediment to digital transformation.
    Business professionals no longer wonder if they'll migrate to the cloud; it's now a matter of when. The cloud environment has proved to be a major force in transitioning to an agile business model that enables quick decisions and fast implementation that solidify customer relationships. And when the cloud is combined with the power of cognitive computing, it drives innovation and transformation that achieves astounding competitive advantage.
    As IoT continues to increase momentum, so does the associated risk. Secure Device Lifecycle Management (DLM) is ranked as one of the most important technology areas of IoT. Driving this trend is the realization that secure support for IoT devices provides companies the ability to deliver high-quality, reliable, secure offerings faster, create new revenue streams, and reduce support costs, all while building a competitive advantage in their markets. In this session, we will use customer use cases...
    Digital Transformation: Preparing Cloud & IoT Security for the Age of Artificial Intelligence. As automation and artificial intelligence (AI) power solution development and delivery, many businesses need to build backend cloud capabilities. Well-poised organizations, marketing smart devices with AI and BlockChain capabilities prepare to refine compliance and regulatory capabilities in 2018. Volumes of health, financial, technical and privacy data, along with tightening compliance requirements by...
    Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settlement products to hedge funds and investment banks. After, he co-founded a revenue cycle management company where he learned about Bitcoin and eventually Ethereal. Andrew's role at ConsenSys Enterprise is a mul...
    The best way to leverage your Cloud Expo presence as a sponsor and exhibitor is to plan your news announcements around our events. The press covering Cloud Expo and @ThingsExpo will have access to these releases and will amplify your news announcements. More than two dozen Cloud companies either set deals at our shows or have announced their mergers and acquisitions at Cloud Expo. Product announcements during our show provide your company with the most reach through our targeted audiences.
    DevOpsSummit New York 2018, colocated with CloudEXPO | DXWorldEXPO New York 2018 will be held November 11-13, 2018, in New York City. Digital Transformation (DX) is a major focus with the introduction of DXWorldEXPO within the program. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term. A total of 88% of Fortune 500 companies from a generation ago are now out of bus...
    With 10 simultaneous tracks, keynotes, general sessions and targeted breakout classes, @CloudEXPO and DXWorldEXPO are two of the most important technology events of the year. Since its launch over eight years ago, @CloudEXPO and DXWorldEXPO have presented a rock star faculty as well as showcased hundreds of sponsors and exhibitors! In this blog post, we provide 7 tips on how, as part of our world-class faculty, you can deliver one of the most popular sessions at our events. But before reading...
    DXWordEXPO New York 2018, colocated with CloudEXPO New York 2018 will be held November 11-13, 2018, in New York City and will bring together Cloud Computing, FinTech and Blockchain, Digital Transformation, Big Data, Internet of Things, DevOps, AI, Machine Learning and WebRTC to one location.
    DXWorldEXPO LLC announced today that "Miami Blockchain Event by FinTechEXPO" has announced that its Call for Papers is now open. The two-day event will present 20 top Blockchain experts. All speaking inquiries which covers the following information can be submitted by email to [email protected] Financial enterprises in New York City, London, Singapore, and other world financial capitals are embracing a new generation of smart, automated FinTech that eliminates many cumbersome, slow, and expe...
    DXWorldEXPO | CloudEXPO are the world's most influential, independent events where Cloud Computing was coined and where technology buyers and vendors meet to experience and discuss the big picture of Digital Transformation and all of the strategies, tactics, and tools they need to realize their goals. Sponsors of DXWorldEXPO | CloudEXPO benefit from unmatched branding, profile building and lead generation opportunities.
    DXWorldEXPO LLC announced today that ICOHOLDER named "Media Sponsor" of Miami Blockchain Event by FinTechEXPO. ICOHOLDER give you detailed information and help the community to invest in the trusty projects. Miami Blockchain Event by FinTechEXPO has opened its Call for Papers. The two-day event will present 20 top Blockchain experts. All speaking inquiries which covers the following information can be submitted by email to [email protected] Miami Blockchain Event by FinTechEXPO also offers s...
    With tough new regulations coming to Europe on data privacy in May 2018, Calligo will explain why in reality the effect is global and transforms how you consider critical data. EU GDPR fundamentally rewrites the rules for cloud, Big Data and IoT. In his session at 21st Cloud Expo, Adam Ryan, Vice President and General Manager EMEA at Calligo, examined the regulations and provided insight on how it affects technology, challenges the established rules and will usher in new levels of diligence arou...
    Dion Hinchcliffe is an internationally recognized digital expert, bestselling book author, frequent keynote speaker, analyst, futurist, and transformation expert based in Washington, DC. He is currently Chief Strategy Officer at the industry-leading digital strategy and online community solutions firm, 7Summits.
    Digital Transformation and Disruption, Amazon Style - What You Can Learn. Chris Kocher is a co-founder of Grey Heron, a management and strategic marketing consulting firm. He has 25+ years in both strategic and hands-on operating experience helping executives and investors build revenues and shareholder value. He has consulted with over 130 companies on innovating with new business models, product strategies and monetization. Chris has held management positions at HP and Symantec in addition to ...
    Cloud-enabled transformation has evolved from cost saving measure to business innovation strategy -- one that combines the cloud with cognitive capabilities to drive market disruption. Learn how you can achieve the insight and agility you need to gain a competitive advantage. Industry-acclaimed CTO and cloud expert, Shankar Kalyana presents. Only the most exceptional IBMers are appointed with the rare distinction of IBM Fellow, the highest technical honor in the company. Shankar has also receive...
    Cloud Expo | DXWorld Expo have announced the conference tracks for Cloud Expo 2018. Cloud Expo will be held June 5-7, 2018, at the Javits Center in New York City, and November 6-8, 2018, at the Santa Clara Convention Center, Santa Clara, CA. Digital Transformation (DX) is a major focus with the introduction of DX Expo within the program. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive ov...