|Oracle Web Cache Administration and Deployment Guide
Part Number A86722-03
This appendix describes common configuration problems and debugging techniques for resolving them. It contains these topics:
If Oracle Web Cache does not start, it can be because of the following problems:
During configuration, you configure a listening port from which Oracle Web Cache receives browser requests. By default, this port is 1100. You also configure listening ports for administration, invalidation, and statistics monitoring requests. By default, these ports are 4000, 4001, and 4002, respectively. In addition to configuring listening ports for Oracle Web Cache, you also configure the advertised port number from which the application Web server(s) can receive Oracle Web Cache requests.
When you start Oracle Web Cache, a port conflict check is performed. If there is a port conflict, Oracle Web Cache will fail to start. Port conflicts are reported to the event log file,
event_log file is located in
$ORACLE_HOME/webcache/logs on UNIX and in
\webcache\logs on Windows NT. Figure E-1 shows an excerpt of
event_log with port conflict event messages.
11/Jan/2001:11:04:42 -0800 -- Error: A failure occurred ( Address already in use ) when assigning a port ( domain: <NONE>, address: 0.0.0.0, port: 1100). Change PORT attribute of the LISTEN element in the configuration file to a suitable unused port. 11/Jan/2001:11:04:42 -0800 -- Error: Failed to start the server. 11/Jan/2001:11:04:42 -0800 -- Error: The server could not initialize 11/Jan/2001:11:04:42 -0800 -- Information: The server is exiting 11/Jan/2001:11:04:05 -0800 -- Warning: The admin server couldn't start the cache server, running in admin-only mode.
Note that the last message will only appear when the
admin server process is started for the first time.
To resolve port conflicts:
Typically, the Oracle Web Cache and the application Web server ports are in conflict. Verify the port assigned to Oracle Web Cache at Administering Web Sites > Oracle Web Cache Listen Port, and verify the host names and ports assigned to the application Web servers at Administering Web Sites > Application Web Servers.
If the administration port is in conflict, the
admin server process will not start, and the Oracle Web Cache Manager will not be accessible. The event log will contain event log messages that resemble the output in Figure E-2.
11/Jan/2001:10:56:11 -0800 -- Error: A failure occurred ( Address already in use ) when assigning a port ( domain: <NONE>, address: 0.0.0.0, port: 4000 ). Change PORT attribute of the LISTEN element in the configuration file to a suitable unused port. 11/Jan/2001:10:56:11 -0800 -- Error: Failed to start the server. 11/Jan/2001:10:56:11 -0800 -- Error: The server could not initialize 11/Jan/2001:10:56:11 -0800 -- Information: The server is exiting
To resolve this port conflict, modify the
webcache.xml file, an internal file that contains the configuration settings, and change the administration port number. The
webcache.xml file is located in
$ORACLE_HOME/webcache on UNIX and in
\webcache on Windows NT. Figure E-3 shows an excerpt of the
webcache.xml file with the line for the administration port shown in boldface.
<?xml version="1.0"?> <!DOCTYPE CALYPSO SYSTEM "internal:///webcache.dtd"> <CALYPSO> <MULTIPORT> <LISTEN IPADDR="ANY" PORT="1100" PORTTYPE="NORM"/> <LISTEN IPADDR="ANY" PORT="4000" PORTTYPE="ADMINISTRATION"/> <LISTEN IPADDR="ANY" PORT="4003" PORTTYPE="INVALIDATION"/> <LISTEN IPADDR="ANY" PORT="4002" PORTTYPE="STATISTICS"/> </MULTIPORT>
Oracle Web Cache pre-allocates a large memory pool for data storage. When Oracle Web Cache is started, the
admin and the
cache server processes require 200 MB of memory to start. If there is not enough physical or virtual memory for these processes, the
cache server process will fail to start. The event log will contain event log messages that resemble the output in Figure E-4.
10/Oct/2000:10:58:02 -0600 -- Error: Oracle Web Cache Cache failed to initialize 10/Oct/2000:10:58:02 -0600 -- Error: The server could not initialize 10/Oct/2000:10:58:02 -0600 -- Information: The server is exiting 10/Oct/2000:10:58:02 -0600 -- Warning: The admin server couldn't start the cache server, running in admin-only mode
To resolve this cache memory issue:
cacheserver processes to start.
Port numbers below 1024 are reserved for use by privileged processes on UNIX. If you want to configure Oracle Web Cache to listen on a port below 1024, such as on port 80, change the ownership of the
webcached executable to
root and run it as
root. By default, the user that performed the installation is the owner of Oracle Web Cache executable.
To configure a privileged port:
The Oracle Web Cache Listen Ports page appears in the right pane.
The Edit/Create Web Cache Listen Ports page dialog box appears.
If Oracle Web Cache was installed by the
root user, change the user ID and group ID to the desired running process identify for Oracle Web Cache. The
webcached executable will still be owned by
root, but it will take on the new process identify once the privileged port is opened.
If Oracle Web Cache was installed by a non-
root user, you may want to change the user ID and group ID to a different user and group ID, such as
To change the process identity:
The Process Identity page appears in the right pane.
root, change the ownership of the
webcachedto the group ID you configured in Step 3.
When Oracle Web Cache starts, it will listen on the privileged port with the new process identity.
If an application Web server has reached capacity the following error message appears when accessing pages of a Web site:
This error indicates that the application Web server has reached capacity--that is, the number of concurrent connections has been exceeded. To resolve this problem, you can either:
In the Administering Oracle Web Cache > Resource Limits page of Oracle Web Cache Manager, check the value of the Current Maximum incoming connections field. This field provides the currently configured capacity. If the capacity can be adjusted, increase it.
If Oracle Web Cache is serving wrong or older content, perform these steps:
access_log, and the event log file,
event_log. If verbose logging is turned on in the event log, error messages about the cacheability rules will be reported.
Configuration changes made in Oracle Web Cache Manager require the following steps:
If these steps are not followed, configuration changes will not take effect.
The currently displayed status message in Oracle Web Cache Manager informs you if one of these steps needs to be performed, or if the Oracle Web Cache is running with the current configuration.
"Status Messages" for further information about status message in Oracle Web Cache Manager