Logging (computing)

Computer data logging In computerized data logging, a computer program may automatically record events in a certain scope in order to provide an audit trail that can be used to diagnose problems.

Examples of physical systems which have logging subsystems include process control systems, and the black box recorders installed in aircraft.

Many operating systems and multitudinous computer programs include some form of logging subsystem. Some operating systems provide a syslog service (described in RFC 3164), which allows the filtering and recording of log messages to be performed by a separate dedicated subsystem, rather than placing the onus on each application to provide its own ad hoc logging system.

In many cases, the logs are esoteric and hard to understand; they need to be subjected to log analysis in order to make sense of them.

It can be useful to combine log file entries from multiple sources. This approach, in combination with statistical analysis, may yield correlations between seemingly-unrelated events on different servers. Other solutions employ network-wide querying and reporting.