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Server Log

Server log and access log settings for the load balancer. When a path information is required, it can be either absolute or relative to $SERVER_ROOT. $SERVER_ROOT is the location where LiteSpeed load balancer is installed. For examples, it can be your_home_dir/lslb, /opt/lslb, or etc. The load balancer executable is under $SERVER_ROOT/bin.

Table of Contents

Server Log

File Name | Log Level | Debug Level | Rolling Size (bytes) | Keep Days | Compress Archive | Enable stderr Log | Enable AIO Logging

Access Log

File Name | Piped Logger | Log Format | Log Headers | Rolling Size (bytes) | Keep Days | Compress Archive

File Name

Description

Specifies the path for the log file.

Syntax

Filename which can be an absolute path or a relative path to $SERVER_ROOT.

Tips

Place the log file on a separate disk.

Log Level

Description

Specifies the level of logging to include in your log file. Available levels (from high to low) are: ERROR, WARNING, NOTICE, INFO and DEBUG. Only messages with level higher or equal to the current setting will be logged.

Syntax

Select from drop down list

Tips

Using DEBUG log level does not have any performance impact, unless Debug Level is set to a level other than NONE. It's recommended to set Log Level to DEBUG and Debug Level to NONE. These settings mean that you will not fill up your hard disk with debug logging, but you will be able to use the Toggle Debug Logging action to control debug output. This action can turn debug logging on and off on the fly, and is useful for debugging busy production servers.

See Also

Debug Level

Debug Level

Description

Specifies the level of debug logging. Log Level must be set to DEBUG to use this feature. Debug logging is disabled when "Debug Level" is set to NONE even if Log Level is set to DEBUG. Toggle Debug Logging can be used to control debug level on a live server without restarting.

Syntax

Select from drop down list

Tips

Important! Always set this to NONE if you do not need detailed debug logging. Active debug logging will severely degrade service performance and potentially saturate disk space in a very short time. Debug logging includes detailed information for each request and response.

It's recommended to set Log Level to DEBUG and Debug Level to NONE. These settings mean that you will not fill up your hard disk with debug logging, but you will be able to use the Toggle Debug Logging action to control debug output. This action can turn debug logging on and off on the fly, and is useful for debugging busy production servers.

See Also

Log Level, Toggle Debug Logging

Rolling Size (bytes)

Description

Specifies when the current log file needs to be rolled over, also known as log rotation. When the file size is over the rollover limit, the active log file will be renamed to log_name.mm_dd_yyyy(.sequence) in the same directory and a new active log file will be created. The actual size of the rotated log file once it is created will sometimes be a little bigger than this size limit. Set to 0 to disable log rotation.

Syntax

Integer number

Tips

Append "K", "M", "G" to the number for kilo-, mega- and giga- bytes.

Keep Days

Description

Specifies how many days the access log file will be kept on disk. Only rotated log files older than the specified number of days will be deleted. The current log file will not be touched regardless how many days worth of data it contains. If you do not want to auto-delete stale and very old log files, set this to 0.

Syntax

Integer number

Compress Archive

Description

Specifies whether to compress rotated log files in order to save disk space.

Syntax

Select from radio box

Tips

Log files are highly compressible and this is recommended to reduce disk usage for old logs.

Enable stderr Log

Description

Specifies whether to write to log when receiving stderr output from processes started by the server.

If enabled, stderr messages will be logged in the same directory as the server log with the fixed name "stderr.log". If disabled, all stderr output will be discarded.

Functions like PHP's error_log() which do not write directly to stderr (file handle 2) are not affected by this setting and will write to the file set in PHP ini directive 'error_log' or the server's "error.log" file with tag '[STDERR]' if that directive is not set.

Syntax

Select from radio box

Tips

Turn it on if you need to debug configured external applications: i.e. PHP, Ruby, Java, Python, Perl.

Enable AIO Logging

Description

Specifies whether to enable AIO logging for server log and access log. If enabled, asynchronous I/O will be used for writing log messages.

Syntax

Select from radio box

Tips

Enabling AIO logging can help overall server performance when server I/O wait is high.

File Name

Description

The access log filename.

Syntax

Filename which can be an absolute path or a relative path to $SERVER_ROOT.

Tips

Put access log file on a separate disk.

Piped Logger

Description

Specifies an external application that will receive the access log data sent by LiteSpeed through a pipe on its STDIN stream (file handle 0). When specified, the access log will be sent to the logger application instead of the access log file specified in previous entry.

LiteSpeed load balancer performs simple load balancing among multiple logger applications if more than one instance of a logger application is configured. LiteSpeed Web Server always attempts to keep the number of logger processes as low as possible. Only when one logger application fails to process access log entries in time will the server attempt to spawn another logger application instance.

If a logger process crashes, the server will start another instance but the log data in the stream buffer will be lost. It is possible to lose log data if external loggers cannot keep up with the speed and volume of the log stream.
File path to the logger application should be given here, and optionally, the number of application instances can be set before the file path, followed by '|'.

Syntax

[<intances>|]<path_to_logger_app>

Example

4|/path/to/logger/app
tells the server to start up to 4 logger processes.

/path/to/logger/app
tells the server to start only one logger process.

Log Format

Description

Specifies the log format for the access log. When log format is set, it will override the Log Headers setting.

Syntax

String. The syntax of log format is compatible with Apache 2.0's custom log format.

Example

Common Log Format (CLF)
"%h %l %u %t \"%r\" %>s %b"

Common Log Format with Virtual Host
"%v %h %l %u %t \"%r\" %>s %b"

NCSA extended/combined log format
"%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\"

Log cookie value of Foobar
"%{Foobar}C"

See Also

Log Headers

Log Headers

Description

Specifies whether to log HTTP request headers: Referer, UserAgent, and Host.

Syntax

Select from checkbox

Tips

Turn this off if you do not need these headers in the access log.

See Also

Log Format