Troubleshooting Load Balancer

Use the information that is provided to help you solve problems that can occur in Load Balancer.

Click a link in the table to go to a full description and possible solution for the problem that you are experiencing.
Table 1. Troubleshooting table for Load Balancer
Symptom Possible Cause Go to...
Dispatcher not running correctly Conflicting port numbers Problem: Load Balancer will not run
Connections from client machines not being served or connections timing out
  • Wrong routing configuration
  • Server does not have loopback device aliased to the cluster address
  • Extra route not deleted
  • Port not defined for each cluster
Problem: Load Balancer requests are not being balanced
Server not serving requests (Windows platform) An extra route has been created in the routing table Problem: Extra routes (Windows 2000)
Dispatcher, Microsoft IIS, and SSL are not working or will not continue Unable to send encrypted data across protocols Problem: Dispatcher, Microsoft IIS, and SSL do not work (Windows platform)
The dscontrol or lbadmin command fails with ‘Server not responding' or ‘unable to access RMI server' message
  1. Commands fail due to socksified stack. Or commands fail due to not starting dsserver
  2. RMI ports are not set correctly
  3. Host file has incorrect local host
Problem: dscontrol or lbadmin command fails
Advisors not working correctly Advisors are not running Problem: Advisors not working correctly
“Cannot Find the File..." error message, when running Netscape as default browser to view online help (Windows platform) Incorrect setting for HTML file association Problem: “Cannot find the file..." error message when trying to view online Help (Windows platform)
Graphical user interface does not start correctly Insufficient paging space Problem: Graphical user interface (GUI) does not start correctly
Graphical user interface does not display correctly. Resolution is incorrect. Problem: Graphical user interface (GUI) does not display correctly
Help panels sometimes disappear behind other windows Java™ limitation Problem: On Windows platform, help windows sometimes disappear behind other open windows
GUI hangs (or unexpected behavior) when trying to load a large configuration file. Java does not have access to enough memory to handle such a large change to the GUI Problem: GUI hangs (or unexpected behavior) when trying to load a large configuration file
Korean Load Balancer interface displays overlapping or undesirable fonts on AIX® and Linux systems Default fonts must be changed Problem: Korean Load Balancer interface displays overlapping or undesirable fonts on AIX and Linux systems
Unexpected GUI behavior when using Windows platform paired with Matrox AGP video card Problem occurs when using Matrox AGP video cards while running the Load Balancer GUI Problem: On Windows platform, unexpected GUI behavior when using Matrox AGP video cards
Slow response time when running commands on the Dispatcher machine Slow response time can be due to machine overloading from a high volume of client traffic Problem: Slow response time running commands on Dispatcher machine
SSL or HTTPS advisor not registering server loads Problem occurs because the SSL server application not configured with the cluster IP address Problem: SSL or HTTPS advisor not registering server loads
Socket pooling is enabled and the Web server is binding to 0.0.0.0 Configure the Microsoft IIS server to be bind specific Problem: Socket pooling is enabled and the Web server is binding to 0.0.0.0
On Windows platform, corrupted Latin-1 national characters appear in command prompt Change font properties of command prompt window Problem: On Windows systems, corrupted Latin-1 national characters appear in command prompt window
On Windows platform, advisors and reach targets mark all servers down Task offloading is not disabled or may need to enable ICMP. Problem: On Windows systems, advisors and reach targets mark all servers down
On Windows platform, advisors not working in a high availability setup after a network outage When the system detects a network outage, it clears its Address Resolution Protocol (ARP) cache Problem: On Windows systems, after network outage, advisors not working in a high availability setup
On Linux systems, "IP address add" command and multiple cluster loopback aliases are incompatible When aliasing more than one address on the loopback device, should use ifconfig command, not ip address add Problem: On Linux systems, do not use "IP address add" command when aliasing multiple clusters on the loopback device
On Solaris systems, Load Balancer processes end when you exit the terminal session window from which they started Use the nohup command to prevent the processes that you started from receiving a hangup signal when you exit the terminal session. Problem: On Solaris systems, Load Balancer processes end when you exit the terminal window from which they started
Slow down occurs when loading Load Balancer configurations The delay might be due to Domain Name System (DNS) calls that are made to resolve and verify the server address. Problem: Delay occurs while loading a Load Balancer configuration
On Windows systems, the following error message appears: There is an IP address conflict with another system on the network If high availability is configured, cluster addresses may be configured on both machines for a brief period which causes this error message to appear. Problem: On Windows systems, an IP address conflict error message appears
On Windows systems, "Server not responding" error occurs when issuing a dscontrol or lbadmin command When more than one IP address exists on a Windows system and the host file does not specify the address to associate with the hostname. Problem: On Windows systems, "Server not responding" error occurs when issuing dscontrol or lbadmin
Dispatcher MAC forwarding configuration limitations with zSeries and S/390 platforms On Linux, there are limitations when using zSeries or S/390 servers that have Open System Adapter (OSA) cards. Possible workarounds are provided. Problem: On Linux, Dispatcher configuration limitations when using zSeries or S/390 servers that have Open System Adapter (OSA) cards
On Linux systems, iptables can interfere with the routing of packets Linux iptables can interfere with load balancing of traffic and must be disabled on the Load Balancer machine. Problem: Linux iptables can interfere with the routing of packets
On Solaris systems, when you try to configure an IPv6 server on the Dispatcher machine, the message "unable to add server" appears This can be caused by the way the Solaris operating system handles the ping request for an IPv6 address. Problem: Unable to add an IPv6 server to the Load Balancer configuration on Solaris systems
A Java fileset warning message appears when installing service fixes or installing natively, using system packaging tools The product installation consists of several packages which are not required to be installed on the same machine, so each of these packages installs a Java fileset. When installed on the same machine a warning messages stating that the Java fileset is also owned by another fileset. Problem: Java warning message appears when installing service fixes
Upgrading the Java fileset provided with the Load Balancer installations If a problem is found with the Java file set, you should report the problem to IBM Service so that you can receive an upgrade for the Java file set that was provided with the Load Balancer installation. Upgrading the Java file set provided with the Load Balancer installation
Client requests fail when forwarding to HP-UX back-end servers After setting up Load Balancer for IPv6 on the HP-UX operating system, client requests to the cluster address fail. This error is a result of the interaction between the neighbor discovery function for the operating system and the Load Balancer. Problem: Client requests fail when using IPv6 MAC forwarding with HP-UX back-end servers
Load Balancer for IPv4 and IPv6 conflicts with IP security (IPsec)

If you are using the Load Balancer for IPv4 and IPv6 with IP security (IPsec) enabled, output packets might be incorrect and dispatcher configuration information might display incorrectly in the command line interface and administrative console for WebSphere Application Server.

Load Balancer reports that it is forwarding connections, but clients do not receive responses.

Problem: On AIX systems, Load Balancer conflicts with IP security (IPsec)
Install program will not run on the 32-bit Linux operating system for zSeries

Installing Load Balancer using ./install on the 32-bit Linux operating system for zSeries produces a "JVM Not Found" message.

Problem: Installing WebSphere Edge Server using ./install on the 32-bit Linux operating system for zSeries produces a "JVM Not Found" message
The uninstall process does not complete successfully on Linux operating systems

The uninstall process for WebSphere Edge Server hangs on Linux operating systems.

Problem: The uninstall process for WebSphere Edge Server hangs on Linux operating systems
The serverUp script might run when you issue commands for Load Balancer that affect the status of servers You might experience problems if you run a command that affects the status of a server, such as the dscontrol manager unquiesce and dscontrol manager quiesce commands, after a manager cycle has already retrieved the weights of the servers. If you run these commands, it might overwrite the values that are saved during the manager cycle and cause the serverUp script to run unexpectedly. Problem: The serverUp script might run when you issue commands for Load Balancer that affect the status of servers


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Last updated: September 10, 2012 09:00 AM EDT
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