DLFlog module
Client Logging in Definable Logging Format
Overview
The DLF module is used to log client requests in a user configurable
format. DLF stands for Definable Logging Format. DLF logs may be
shared by groups of virtual servers, and log files are automatically
rotated every night at midnight.
Configuration
To enable DLF logging you need to specify a location for the log file
and a format string. The file location
should be an absolute path. The format string is a free format text
string containing the macros detailed in the DLF
format documentation.
Once the information has been entered click on the update button to commit the changes.
If you prefer, you can optionally use a predefined default log format. Select the format you require and click on the choose button to commit the changes. The differences between formats are outlined here.
Automatic Rotation
DLF logfiles are automatically rotated at midnight each night when in
use by at least one virtual server. The logging information for the
day is moved to filename.YYYYMMDD where filename is
the filename of the DLF logfile and YY, MM,
DD are year, month and day respectively. The original
logfile is then emptied, and logging for the subsequent day continues
in that file until the next rotation happens.
Sharing logfiles
Several virtual servers can be configured to log to the same file.
This allows individual virtual hosts to be grouped logically
together. For example, www.mycompany.com and www.mycompany.co.uk can
both log to the same set of files.
Using group or single log files under UNIX operating systems has the added advantage of reducing the number of file descriptors in use. This is relevant when running a large number of virtual servers on a single machine, as the number of file descriptors is limited by the operating system.