Oracle Web Cache Administration and Deployment Guide Release 1.0.2.3 Part Number A86722-03 |
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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
. The event_log
file is located in $ORACLE_HOME/webcache/logs
on UNIX and in ORACLE_HOME
\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 ORACLE_HOME
\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:
admin
and the cache
server 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.
webcached
executables.
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 nobody
/nobody
.
To change the process identity:
root
, change the ownership of the webcached
executable to root
.
webcached
to the group ID you configured in Step 3.
chgrp group_id
$ORACLE_HOME/webcache/bin/webcached
webcached
executable.
chmod u+s $ORACLE_HOME/webcache/bin/webcached
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:
The application Web server is busy. Possible reach capacity.
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.
See Also:
"Status Messages" for further information about status message in Oracle Web Cache Manager |
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