Skip to main content

System log

Each MooseFS module will send certain messages to the system log (syslog). The number of logged messages depends on how busy the system is and if the instance is healthy or if it has some issues (hardware issues, network issues). All MooseFS modules send logs in the same format and all the logs are assigned to one of five severity levels (detailed description below). MooseFS has almost 3000 possible messages, most of which never appear in a healthy instance, but in case of problems the modules can become quite verbose, to help the system admin diagnose any problems that may arrise.

Log entry format​

Each entry in the system log has the following format:

date host process: [error level] error message

Where:

  • date is the date in operating system specfied format
  • host is (usually) the local hostname
  • process is the indicator of the process that logged the message and consist of process name and/or process ID
  • error level is MooseFS definied severity level (see below)
  • error message is a short description of what has happend, whether it's an error or just an expected occurence

Log levels​

All possible messages in MooseFS are divided into following severity levels:

  • error - an unrecoverable error that will eventually result in the module ending its work
  • warning - a serious error, that the module will try to circumvent or repair somehow, but should be cause for immediate concern and repair effort from the system admin
  • notice - an undesired behaviour or occurence in the module, but something the system can cope with; messages of this type should cause concern depending on how often they appear vs. how busy a particular module is
  • info - a regular information, not indicating any error, but perhaps useful for the system admin
  • debug - debug information, normally not visible, may be recorded in test version of a module or when certain, non standard options are turned on

The above log levels correspond with standard syslog error levels. However, MooseFS modules have two variables that allow for some control over logging:

  • SYSLOG_MIN_LEVEL - indicates the minimum level of messages, that should be logged; default value is INFO, which means that all the messages with info and higher (up to error) levels will be logged
  • SYSLOG_ELEVATE_TO - every error message is logged with the same syslog erorr level as its MooseFS error level, except for messages with MooseFS error level set by SYSLOG_ELEVATE_TO and below, which will all be logged with exactly the SYSLOG_ELEVATE_TO level; default value is NOTICE, which means that all messages with notice, info and debug (if any) levels will be sent to syslog with level notice; this does not change the notation in the message line, just the (numeric) logging level sent to syslog