Logging Levels

-
Most popular logging frameworks (e.g. Log4J, SLF4J, Log4Net, EntLib) allow for several logging levels to be instrumented. A common question is: What logging levels are appropriate under what scenarios? The following lists some common log levels are their usage:
  • Fatal -
    • Service/ application/ process about to terminate.
    • Unable to proceed with normal operation.
    • Force a shutdown to prevent (further) data loss.
    • Examples:
      • No more system resource (OOM)
  • Error -
    • Unhandled or unexpected system error has occurred.
    • Current operation/ thread to be aborted.
    • Issue needs to be fixed.
    • Still able to continue with normal operation (at least for other users/ sessions) otherwise.
    • Examples:
      • database deadlock
      • Unexpected/ unhandled exception
      • Runtime errors
      • Transaction aborted
      • Can't create file
  • Warn -
    • Things are generally working fine.
    • Recoverable conditions.
    • Transient environmental conditions happened.
    • Something happened (but was handled) that may potentially turn into error conditions soon but has yet to happen.
    • Examples:
      • number of connections getting low
      • operation timeout
      • CPU utilisation reaches 80%
      • data unavailable; using cached/ default values
  • Info -
    • Useful and important information for logging.
    • No cause for concern.
    • A normal & expected event happened.
    • Useful in the running and management of the system.
    • Examples:
      • Successful initialisation
      • Starting/ stopping of services
      • Successful transactions
  • Debug -
    • Useful in troubleshooting in production environment but otherwise, should only be used in development and testing environments.
    • Used by IT professionals (e.g. developers, system admins, etc.).
  • Trace -
    • Detailed tracing and logging.
    • Specifically for developers only.

Comments

Post a Comment

Popular posts from this blog

Understanding ITIL Service Management the UML way…

-
Image
I originally had a great deal of difficult reconciling the differences amongst ITIL Change Management, Incident Management, and Problem Management. Having researched on the subjects and understanding them better now, I’ve tried to put the concepts together using a UML class diagram to capture my understanding and to keep it imprinted. Similarly, I wanted to differentiate the various categories of changes (Standard, Emergency, Normal) using an easy to understand & self-explanatory manner – a UML Activity Diagram!
Read more

Apache Web Server Troubleshooting

-
How to troubleshoot Apache Web Server? A few standard commands to know by hard: To confirm the modules that are or will be loaded in Apache: apachectl –M [-f <conf filename>] To check the virtual host load pattern: apachectl –S [-f <conf filename>] To test a httpd.conf file: apachectl –t [-f <conf filename>] To maintain the http server: apachectl start|stop|restart To start with a specified configuration file: apachectl –f <conf filename> Create a minimalist httpd.conf. Something like: Listen 80 ServerName myserver.com:80 ServerAdmin admin@myserver.com #ServerRoot " . " ServerRoot " /usr/local/apache2 " User nobody Group nobody #DocumentRoot " ..\wwwroot " DocumentRoot " /home/data/html " ErrorLog " logs/basic_apache.log " LogLevel debug #LoadModule log_config_module modules/mod_log_config.dll LoadModule log_config_module modules/mod_log_config.so <IfModule log_config_module> LogFormat " %h %l
Read more