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Oracle® HTTP Server Administrator's Guide
10g Release 2 (10.1.2) B14007-04 |
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Oracle® HTTP Server Administrator's Guide
10g Release 2 (10.1.2) B14007-04 |
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Previous |
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This chapter provides an overview of the Oracle HTTP Server processes, and provides information on how to regulate, and monitor these processes.
Topics discussed are:
Documentation from the Apache Software Foundation is referenced when applicable.
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Note: Readers using this guide in PDF or hard copy formats will be unable to access third-party documentation, which Oracle provides in HTML format only. To access the third-party documentation referenced in this guide, use the HTML version of this guide and click the hyperlinks. |
Once Oracle HTTP Server is started, the system is ready to listen for and respond to http(s) requests. The request processing model on UNIX differs from that on Windows.
On UNIX, there is a single parent process that manages multiple child processes. The child processes are responsible for handling requests. The parent process brings up additional child processes as necessary, based on configuration. Although the server has the ability to dynamically bring up additional child processes, it is best to configure the server to start enough children initially so that requests can be handled without having to spawn more child processes.
On Windows, there is a single parent process and a single child process. The child process creates threads that are responsible for handling client requests. The number of threads created is static and can be configured.
By default, on UNIX, the main httpd parent process and child processes are configured to run as the user who installed Oracle Application Server. The User and Group directives are used to set the privileges for the child processes. These directives are ignored if you are not running as root. The child processes must be able to read all the content that will be served.
Use the following directives to manage the server processes:
Provides the following two options, both being applicable to UNIX only:
inetd: Starts up a new child process every time a request comes in. The program exits once the request is dealt with. This setting eliminates the option of having several child processes in waiting, making it slower and expensive, but more secure. This option should be avoided, if possible.
standalone: Enables several waiting child processes, and requires the server to be started only once. It is the default and recommended setting for a busy Web site.
You must specify the User and Group under which the servers answer requests.
For example: ServerType standalone
Specifies the group under which the server answers requests. Run the standalone server as root to use this directive. It is recommended that you create a new group for running the server. This is applicable to UNIX only.
For example: Group myorg
Specifies the user ID to which the server answers requests. Run the standalone server as root to use this directive.You should have privileges to access files that are available for everyone, and should not be able to execute code which is not meant for httpd requests. It is recommended that you set up a new user for running the server. This is applicable to UNIX only.
For example: User jdoe
The following directives tune the performance of Oracle HTTP Server by configuring how clients requests are processed. They are located in the "Global Environment" of the httpd.conf file.
Sets the number of child server processes created when Oracle HTTP Server is started. The default is 5. This is applicable to UNIX only.
Usage: StartServers 5
Controls the maximum number of child threads handling requests. The default is 50. This is applicable to Windows only.
Usage: ThreadsPerChild 50
Limits the number of requests that can be dealt with at one time. The default and recommended value is 150. This is applicable to UNIX only.
Usage: MaxClients 150
Controls the number of requests a child process handles before it dies. If you set the value to 0, which is the default, then the process will never die.
On Windows, it is recommended that this be set to 0. If it is set to a non-zero value, when the request count is reached, the child process exits, and is respawned, at which time it re-reads the configuration file. This can lead to unexpected behavior if you have modified a configuration file, but are not expecting the changes to be applied yet.
Usage: MaxRequestsPerChild 0
Sets the maximum number of idle child server processes. An idle process is one which is running, but not handling a request. The parent process kills off idle child processes that exceed the value set for this directive. The default is 20. This is applicable to UNIX only.
Usage: MaxSpareServers 20
Sets the minimum number of idle child server processes. An idle process is one which is running but not handling a request. The parent process will create new children at the maximum rate of one process per second if there are fewer processes running. The default is 5. This is applicable to UNIX only.
Usage: MinSpareServers 5
On UNIX, if you want to run on ports less than 1024, then you will have to run as root.
In order to run Oracle HTTP Server as root, perform the following steps:
Stop Oracle HTTP Server using Application Server Control Console, or with the following command:
ORACLE_HOME/opmn/bin> opmnctl [verbose] stopproc ias-component=HTTP_Server
Change to root user.
Navigate to ORACLE_HOME/Apache/Apache/bin and execute the following command:
chown root .apachectl chmod 6750 .apachectl
Exit root.
Restart Oracle HTTP Server using Application Server Control Console, or with the following command:
ORACLE_HOME/opmn/bin> opmnctl [verbose] restartproc ias-component=HTTP_Server
For additional security on UNIX, you can change the user to "nobody". Be sure that the child processes can accomplish their tasks as the user "nobody". Change all static content, such as the ORACLE_HOME/Apache/Apache/htdocs directory, so that all the files are readable, but ideally not writable by the user "nobody". Also, verify that all the CGI and FastCGI programs can be run by user "nobody".
If your PL/SQL application is using the file-system caching functionality in mod_plsql, then the httpd processes should have read and write privileges to the cache directory through the parameter PlsqlCacheDirectory in ORACLE_HOME/Apache/modplsql/conf/cache.conf on UNIX or ORACLE_HOME\Apache\modplsql\conf\cache.conf on Windows. By default, this parameter points to ORACLE_HOME/Apache/modplsql/cache on UNIX or ORACLE_HOME\Apache\modplsql\cache on Windows.
For Oracle Application Server Portal, the content cached by mod_plsql is used, or updated by the Parallel Page Engine running under OC4J Portal. This means that the cache directory is readable and writable by the OC4J Portal process as well. If Oracle HTTP Server is configured to run as "nobody", then OC4J_Portal should also run as the same user.
Finally, given that the cached content might contain sensitive data, the final contents of the file-system cache should be protected. So, although Oracle HTTP Server might run as "nobody", access to the system as this user should be well-protected.
There are several ways to monitor Oracle HTTP Server processes.
Use Oracle Enterprise Manager 10g Application Server Control Console to monitor Oracle HTTP Server processes.
If a network error occurs on a device such as a router or firewall between the application server and the database, JDBC connections may stop responding. In this situation, you must stop Oracle HTTP Server manually, and there may be a delay in stopping the processes.
Use the performance monitor on Windows, or the ps utility on UNIX.
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See Also: Oracle Application Server Performance Guide and your operating system documentation for more information. |
Use mod_status for server status. By default, it is available from localhost only.
