Rotating the log files of the data server and display server
Rotating a log file refers to closing a log file being used by a running data server or display server and opening a new log file to be used instead from that point onwards. This lets you archive log files and avoid log files that are too large to easily view.
Each site should decide on and implement its own log rotation policy. You should consider the following:
How often to rotate log files.
How large a log file for a data server or display server can be.
What log file naming conventions to use to organize log files.
There is a lot of useful header information in the log file being used when the data server or display server starts. If you need to provide log files to Apama technical support, you should be able to provide the log file that was in use when the data server or display server started, as well as any other log files that were in use before and when a problem occurred.
Logging for data servers and display servers is configured using standard Log4j configuration files. You can find them in the etc directory of your Apama installation:
dashboard-server-log4j.properties is the configuration file for the data server.
display-server-log4j.properties is the configuration file for the display server.
By default, the above files configure the servers to rotate the log files when they reach a certain file size. But there are comments in the configuration files showing how to enable time-based rotation instead. This can be used, for example, to rotate the log files on a monthly basis.
There are many external resources which can be found online regarding how to configure Log4j for different purposes. In the case of more advanced configurations, you may consider consulting these.
Note: Some people use the term "log rolling" instead of "log rotation".