rotatelogs
write to log files over 2GB?Platform | 1.3 releases? | 6.1 and earlier? | 7.0 and later? |
---|---|---|---|
AIX, HP-UX/PA-RISC, Linux, Solaris/SPARC | No | No | Yes |
HP-UX/PA-RISC, Solaris/x86_64, z/OS | N/A | Yes | Yes |
Windows | No | Yes | Yes |
This applies to IBM HTTP Server 2.0 through 6.1.
The web server and rotatelogs use file access interfaces provided by the Apache Portable Runtime (APR) library bundled with IBM HTTP Server. The APR provided with IBM HTTP Server on these platforms cannot support file offsets larger than 2GB without introducing an API incompatibility, which would break all current plug-in modules written for IBM HTTP Server. However, it was possible to enable large file support for applications which only append to files without introducing an API incompatibility.
The web server's internal support for error and access log files only appends to the end of log files and does not use file offsets, so the modifications to APR allow large log files when using the internal web server support.
The rotatelogs application interacts with log files in a more complex manner, including the use of file offsets. Thus, the APR changes don't enable large file support in rotatelogs.
For releases 7.0 and later, the bundled APR allows rotatelogs to use large file offsets. Note that since rotatelogs has a static copy of the APR library, rotatelogs from later releases can be used as a piped logger in previous releases.
No, the rotate operation will not occur until IHS logs another request. If your configuration specifies that rotatelogs performs the rotation operation after 86400 seconds, and if IHS receives no requests after 86400 seconds have elapsed, the new log file will not yet be created. Then, when rotatelogs receives its next request to log, it will create the new log file and close the old one.
No. However, data may be buffered in the operating system kernel after the web server writes the data but before rotatelogs can read it. This time is usually very brief.
Other programs can be used to filter data seen by rotatelogs, and those programs may introduce buffering. Example:
CustomLog "|grep -v \b200\b | /opt/IHS/bin/rotatelogs /opt/IHS/logs/grepped 86400 540" common
In this case, grep will buffer data internally until it has a full buffer, then rotatelogs will see many log records at the same time. (4096 bytes is a typical size for the buffer used by grep.)
Note: IBM HTTP Server 6.0 prior to 6.0.2.1, or IBM HTTP Server 2.0 prior to PK07831, does not support the type of CustomLog directive in the example above.
Example:
CustomLog "|/usr/HTTPServer/bin/rotatelogs -l /www/logs/access_%Y-%m-%d" custom
This example includes the year, month, and day in the log file
name. An example generated filename is
/www/logs/access_2007-11-26
.
error writing to logfile xxx messages lost
This message can also occur when there is insufficient free space on the filesystem used for logging.
If this error message occurs, the log file being written to by rotatelogs will be truncated and then new entries will continue to be written to the log.
The supported OS versions can be seen at:
WebSphere Application Server detailed system requirements
Refer to the 'Software and hardware requirements / Application Server / Windows' sections
You can use Windows XP for general development and testing purposes, but this is a limitation that you may experience.
Refer to How can I rotate (switch) log files? for additional information on other possible alternatives.
This behavior is the same in versions 6.x and the newer 7.0 versions of IBM HTTP Server and is a limitation of using piped loggers.
A graceful restart of the service after the logs rotate should allow the rotated logs to be removed. The restart of the web server will relinquish the reference to the original error log, and the rotatelogs associated with the parent will then have a reference to the current error log.
Another workaround would be to install and enable the mod_mpmstats
module with the ReportInterval
directive set to occasionally write
the thread usage report to the error log. With this module, the
parent process is performing periodic writes to the error log, and
in doing so, the parent's log reference will be updated to the current
error log on a regualr basis, and it will no longer have the reference
to the original error log. This will allow the original log to be
deleted.
For IHS 6,x, you can obtain the mod_mpmstats
module by downloading the
ihsdiag
package at this url:
MustGather: Debugging IBM HTTP Server crashes, hangs, high CPU, startup failures
For IHS 7.0, you can find this module in the '/modules/debug
' directory.
You can find enablement and usage info for the module at:
http://publib.boulder.ibm.com/httpserv/ihsdiag/2.0/mod_mpmstats.html
IBM HTTP Server 6.1 and earlier must use the full filesystem path to the piped logger. The piped logger
cannot be specified relative to the ServerRoot
. The operative part of the error message in this
FAQ is that the path is not absolute.
IBM HTTP Server 7.0 and later support a relative path to a piped logger.