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Oracle® Fusion Middleware Administrator's Guide for Oracle HTTP Server
11g Release 1 (11.1.1)

Part Number E10144-06
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7 Managing Oracle HTTP Server Logs

Note:

Unless otherwise mentioned, the information in this document is applicable when Oracle HTTP Server is installed with Oracle WebLogic Server and Oracle Fusion Middleware Control. It is assumed that readers are familiar with the key concepts of Oracle Fusion Middleware, as described in the Oracle Fusion Middleware Concepts Guide and the Oracle Fusion Middleware Administrator's Guide.

For information about installing Oracle HTTP Server in standalone mode, see “Installing Oracle Web Tier Without Oracle WebLogic Server” in the Oracle Fusion Middleware Installation Guide for Oracle Web Tier.

Oracle HTTP Server generates log files containing messages that record all types of events, including startup and shutdown information, errors, warning messages, access information on HTTP requests, and additional information. This chapter describes how to find information about the cause of an error and its corrective action, to view and manage log files to assist in monitoring system activity and to diagnose problems.

This chapter includes the following sections:

7.1 Overview of Server Logs

You can view Oracle Fusion Middleware log files using either Fusion Middleware Control or a text editor. The log files for Oracle HTTP Server are located in the following directory:

ORACLE_INSTANCE/diagnostics/logs/OHS/component_name

There are two types of logs for Oracle HTTP Server:

This section contains the following topics:

7.1.1 About Error Logs

Oracle HTTP Server enables you to choose the format in which you want to generate log messages. You can choose to generate log messages in the legacy Apache message format, or use Oracle Diagnostic Logging (ODL) to generate log messages in text or XML-formatted logs, which complies with Oracle standards for generating error log messages.

By default, Oracle HTTP Server error logs use ODL for generating diagnostic messages. It provides a common format for all diagnostic messages and log files, and a mechanism for correlating the diagnostic messages from various components across Oracle Fusion Middleware.

The default name of the error log file is component_name.log.

7.1.2 About Access Logs

Access logs record all requests processed by the server. The logs contain basic information about every HTTP transaction handled by the server. The access log contains the following information:

  • Host name

  • Remote log name

  • Remote user and time

  • Request

  • Response code

  • Number of transferred bytes

The default name of the access log file is access_log.

Access Log Format

You can specify the information to include in the access log, and the manner in which it is written. The default format is the Common Log Format (CLF).

The CLF format contains the following fields:

host ident authuser date request status bytes

  • host: This is the client domain name or its IP number. Use %h to specify the host field in the log.

  • ident: If IdentityCheck is enabled and the client system runs identd, this is the client identity information. Use %i to specify the client identity field in the log.

  • authuser: This is the user ID for the authorized user. Use %a to specify the authorized user field in the log.

  • date: This is the date and time of the request in the day/month/year:hour:minute:second format. Use %t to specify date and time in the log.

  • request: This is the request line, in double quotes, from the client. Use %r to specify request in the log.

  • status: This is the three-digit status code returned to the client. Use %s to specify the status in the log. If the request will be forwarded from another server, use %>s to specify the last server in the log.

  • bytes: This is the number of bytes, excluding headers, returned to the client. Use %b to specify number of bytes in the log. Use %i to include the header in the log.

See Also:

Access Log in the Apache HTTP Server documentation.

7.1.3 Log Rotation

Oracle HTTP Server supports two types of log rotation policies: size-based and time-based. You can configure the Oracle HTTP Server logs to use either of the two rotation polices, by using the odl_rotatelogs command. By default, Oracle HTTP Server uses odl_rotatelogs for both error and access logs.

odl_rotatelogs supports all the features of Apache's rotatelogs command and the additional feature of log retention.

The following is the general syntax of the odl_rotatelogs command:

odl_rotatelogs [-u:offset] logfile {size-|time-based-rotation-options}

Table 7-1 describes the size- and time-based rotation options:

Table 7-1 Options of the odl_rotatelogs command

Option Description

-u

The time (in seconds) to offset from UTC.

logfile

The path and name of the log file, followed by a hyphen (-) and then the timestamp format.

The following are the common timestamp format strings:

  • %m: Month as a two-digit decimal number (01-12)

  • %d: Day of month as a two-digit decimal number (01-31)

  • %Y: Year as a four-digit decimal number

  • %H: Hour of the day as a two-digit decimal number (00-23)

  • %M: Minute as a two-digit decimal number (00-59)

  • %S: Second as a two-digit decimal number (00-59)

It should not include formats that expand to include slashes.

frequency

The time (in seconds) between log file rotations.

retentionTime

The maximum time for which the rotated log files are retained.

startTime

The time when time-based rotation should start.

maxFileSize

The maximum size (in MB) of log files.

allFileSize

The total size (in MB) of files retained.


Syntax and Examples for Time- and Size-Based Rotation

  • Time-based rotation

    Syntax:

    $ odl_rotatelogs logfile frequency retentionTime startTime
    

    Example:

    $ odl_rotatelogs /varlog/error.log-%Y-%m-%d 21600 172800 2012-03-10T08:30:00
    

    This command configures log rotation to be performed every 21600 seconds (6 hours) starting from 8:30 a.m. on March 10, 2012, and it specifies that the rotated log files should be retained for 172800 seconds (2 days).

  • Size-based rotation

    Syntax:

    $ odl_rotatelogs logfile maxFileSize allFileSize
    

    Example:

    This command configures log rotation to be performed when the size of the log file reaches 10 MB, and it specifies the maximum size of all the rotated log files as 70 MB (up to 7 log files (=70/10) will be retained).

    $ odl_rotatelogs /var/log/error.log-%Y-%m-%d 10M 70M
    

7.2 Configuring Oracle HTTP Server Logs

You can use Fusion Middleware Control to configure error and access logs. The following logging tasks can be set from the Log Configuration page:

7.2.1 Using Fusion Middleware Control to Configure Error Logs

To configure an error log for Oracle HTTP Server using Fusion Middleware Control, do the following:

  1. Navigate to the Oracle HTTP Server home page.

  2. Select Log Configuration from the Administration menu.

    The Log Configuration page is displayed, as shown in the following figure.

    Log configuration screen
    Description of the illustration log_config_11g.gif

  3. The following error log configuration tasks can be set from this page:

7.2.1.1 Configuring the Error Log Format and Location

Oracle HTTP Server by default uses ODL-Text as the error log format and creates the log file with the name component_name.log under the ORACLE_INSTANCE/diagnostics/logs/OHS/ component_name directory. To use a different format or log location, do the following:

  1. From the Log Configuration page, navigate to the General section under the Error Log section.

  2. Select the desired file format. Although both ODL-Text and ODL-XML formats provide the same information, the ODL-XML file includes XML elements and wrappers, and so may be easier to read.

    • ODL-Text – the format of the diagnostic messages conform to an Oracle standard and are written in text format.

    • ODL-XML – the format of the diagnostic messages conform to an Oracle standard and are written in XML format.

    • Apache – the format of the diagnostic messages conform to the legacy Apache HTTP Server message format.

  3. Enter a path for the error log in the Log File/Directory field. This directory must exist before you enter it here.

  4. Review the settings. If the settings are correct, click Apply to apply the changes. If the settings are incorrect, or you decide to not apply the changes, click Revert to return to the original settings.

  5. Restart Oracle HTTP Server. See Section 4.1.4.

7.2.1.2 Configuring the Error Log Level

You can configure the amount and type of information written to log files by specifying the message type and level. Error log level for Oracle HTTP Server by default is configured to WARNING:32. To use a different error log level do the following:

  1. From the Log Configuration page, navigate to the General section under the Error Log section.

  2. Select a level for the logging from the Level menu. The higher the log level, the more information that is included in the log.

  3. Review the settings. If the settings are correct, click Apply to apply the changes. If the settings are incorrect, or you decide to not apply the changes, click Revert to return to the original settings.

  4. Restart Oracle HTTP Server. See Section 4.1.4.

Note:

The log levels are different for the Apache log format from ODL-Text and the ODL-XML log format.

7.2.1.3 Configuring Error Log Rotation Policy

Log rotation policy for error logs can either be time-based, such as once a week, or sized-based, such as 120MB. By default, the error log file is rotated when it reaches 10 MB in size and a maximum of 7 error log files will be retained. To use a different rotation policy, do the following:

  1. From the Log Configuration page, navigate to the General section under the Error Log section.

  2. Select a rotation policy.

    • No Rotation – if you do not want to have the log file rotated ever.

    • Size Based – rotate the log file whenever it reaches a configured size. Set the maximum size for the log file in Maximum Log File Size (MB) field and the maximum number of error log files to retain in Maximum Files to Retain field.

    • Time Based – rotate the log file whenever configured time is reached. Set the start time, rotation frequency, and retention period.

  3. Review the settings. If the settings are correct, click Apply to apply the changes. If the settings are incorrect, or you decide to not apply the changes, click Revert to return to the original settings.

  4. Restart Oracle HTTP Server. See Section 4.1.4.

7.2.2 Using Fusion Middleware Control to Configure Access Logs

To configure an access log for Oracle HTTP Server using Fusion Middleware Control, do the following:

  1. Navigate to the Oracle HTTP Server home page.

  2. Select Log Configuration from the Administration menu.

The following access log configuration tasks can be set from this page:

7.2.2.1 Configuring the Access Log Format

Log format specifies the information included in the access log file and the manner in which it is written. To add a new access log format or to edit or remove an existing format, do the following:

  1. From the Log Configuration page, navigate to the Access Log section.

  2. Click Manage Log Formats.

    The Manage Custom Access Log Formats page is displayed, as shown in the following figure.

    Access log format page
    Description of the illustration log_format_11g.gif

  3. Select an existing format to change or remove, or click Add Row to create a new format.

  4. If you choose to create a new format, then enter the new log format in the Log Format Name field and the log format in the Log Format Pattern field.

    See Also:

    Refer to the Apache HTTP Server documentation for information about log format directives.

  5. Click OK to save the new format.

7.2.2.2 Configuring the Access Log File

To configure an access log for file Oracle HTTP Server, do the following:

  1. From the Log Configuration page, navigate to the Access Log section.

  2. Click Create to create a new access log, or select a row from the table and click Edit button to edit an existing access log file.

    The Create or Edit Access Log page is displayed.

    Access log format page
    Description of the illustration log_access.gif

  3. Enter the path for the access log in the Log File Path field. This directory must exist before you enter it.

  4. Select an existing access log format from the Log Format menu.

  5. Select a rotation policy.

    • No Rotation – if you do not want to have the log file rotated ever.

    • Size Based – rotate the log file whenever it reaches a configured size. Set the maximum size for the log file in Maximum Log File Size (MB) field and the maximum number of error log files to retain in Maximum Files to Retain field.

    • Time Based – rotate the log file whenever configured time is reached. Set the start time, rotation frequency, and retention period.

  6. Click OK to continue.

    Note that you can create multiple access log files.

7.3 Log Directives for Oracle HTTP Server

This section discuss Oracle HTTP Server error and access log-related directives in the httpd.conf file. The directives discussed are:

7.3.1 Oracle Diagnostic Logging Directives

Oracle HTTP Server by default uses Oracle Diagnostic Logging (ODL) for generating diagnostic messages. The following directives are used to setup logging using ODL:

7.3.1.1 OraLogMode

Enables you to choose the format in which you want to generate log messages. You can choose to generate log messages in the legacy Apache, ODL text, or ODL XML format.

OraLogMode Apache | ODL-Text | ODL-XML

Default value: ODL-Text

For example: OraLogMode ODL-XML

Note:

The Apache log directives ErrorLog and LogLevel are only effective when OraLogMode is set to Apache. When OraLogMode is set to either ODL-Text or ODL-XML, the ErrorLog and LogLevel directives are ignored.

7.3.1.2 OraLogDir

Specifies the path to the directory that contains all log files. This directory must exist.

This directive is used only when OraLogMode is set to either ODL-Text or ODL-XML. When OraLogMode is set to Apache, OraLogDir is ignored and ErrorLog is used instead.

OraLogDir <path>

Default value: ORACLE_INSTANCE/diagnostics/logs/OHS/component_name

For example: OraLogDir /tmp/logs

7.3.1.3 OraLogSeverity

Enables you to set message severity. The message severity specified with this directive is interpreted as the lowest desired message severity, and all messages of that severity level and higher are logged.

This directive is used only when OraLogMode is set to either ODL-Text or ODL-XML. When OraLogMode is set to Apache, OraLogSeverity is ignored and LogLevel is used instead.

OraLogSeverity <msg_type>[:msg_level]

Default value: WARNING:32

For example: OraLogSeverity NOTIFICATION:16

msg_type

Message types can be specified in upper or lower case, but appear in the message output in upper case. This parameter must be of one of the following values:

  • INCIDENT_ERROR

  • ERROR

  • WARNING

  • NOTIFICATION

  • TRACE

msg_level

This parameter must be an integer in the range of 1–32, where 1 is the most severe, and 32 is the least severe. Using level 1 will result in fewer messages than using level 32.

7.3.1.4 OraLogRotationParams

Enables you to choose the rotation policy for an error log file. This directive is used only when OraLogMode is set to either ODL-Text or ODL-XML. When OraLogMode is set to Apache, OraLogRotationParams is ignored.

OraLogRotationParams <rotation_type> <rotation_policy>

Default value: S 10:70

For example: OraLogRotationParams T 43200:604800 2009-05-08T10:53:29

rotation_type

This parameter can either be S (for sized-based rotation) or T (for time-based rotation).

rotation_policy

When rotation_type is set to S (sized-based), set the rotation_policy parameter to:

maxFileSize:allFilesSize (in MB)

For example, when configured as 10:70, the error log file is rotated whenever it reaches 10MB in size and a total of 70MB is allowed for all error log files (a maximum of 70/10=7 error log files will be retained).

When rotation_type is set to T (time-based), set the rotation_policy parameter to:

frequency(in sec) retentionTime(in sec) startTime(in YYYY-MM-DDThh:mm:ss)

For example, when configured as 43200:604800 2009-05-08T10:53:29, the error log is rotated every 43200 seconds (that is, 12 hours), rotated log files are retained for maximum of 604800 seconds (7 days) starting from May 5, 2009 at 10:53:29.

7.3.2 Apache HTTP Server Log Directives

Although Oracle HTTP Server uses ODL by default for error logs, you can configure the OraLogMode directive to Apache to generate error log messages in the legacy Apache HTTP Server message format. The following directives are discussed in this section:

7.3.2.1 ErrorLog

The ErrorLog directive sets the name of the file where the server logs any errors it encounters. If the file-path is not absolute then it is assumed to be relative to the ServerRoot.

This directive is used only when OraLogMode is set to Apache. When OraLogMode is set to either ODL-Text or ODL-XML, ErrorLog is ignored and OraLogDir is used instead.

See Also:

For information about the ErrorLog directive, see the Apache HTTP Server documentation .

7.3.2.2 LogLevel

The LogLevel directive adjusts the verbosity of the messages recorded in the error logs.

This directive is used only when OraLogMode is set to Apache. When OraLogMode is set to either ODL-Text or ODL-XML, LogLevel is ignored and OraLogSeverity is used instead.

See Also:

Refer to the Apache HTTP Server documentation for information about the LogLevel directive.

7.3.2.3 LogFormat

The LogFormat directive specifies the format of the access log file. By default, Oracle HTTP Server comes with the following four access log formats defined:

LogFormat "%h %l %u %t \"%r\" %>s %b" common
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent

See Also:

Refer to the Apache HTTP Server documentation for information about the LogFormat directive.

7.3.2.4 CustomLog

The CustomLog directive is used to log requests to the server. A log format is specified and the logging can optionally be made conditional on request characteristics using environment variables. By default, the access log file is configured to use the common log format.

See Also:

Refer to the Apache HTTP Server documentation for information about the CustomLog directive.

7.4 Viewing Oracle HTTP Server Logs

You can search, view, and list Oracle HTTP Server log files using Fusion Middleware Control, or you can download a log file to your local client and view the log files using another tool.

You can also use the text editor of your choice to view Oracle HTTP Server log files directly from the ORACLE_INSTANCE directory. By default, Oracle HTTP Server log files are located in the ORACLE_INSTANCE/diagnostics/logs/OHS/component_name directory.

As discussed in Section 7.1, "Overview of Server Logs", there are mainly two types of log files for Oracle HTTP Server: error logs and access logs. The error log file is an important source of information for maintaining a well-performing server. The error log records all of the information about problem situations so that the system administrator can easily diagnose and fix the problems. The access log file contains basic information about every HTTP transaction that the server handles. This information can be used to generate statistical reports about the server's usage patterns.

See Also:

For information about searching and viewing log files, see the Oracle Fusion Middleware Administrator's Guide