The software should be viewed as a toolkit of Perl modules which can be used as seen fit by a sys-admin, for example:

• by writing an application script to be run as a daemon --- symon is a simple such script (an obvious improvement would be to make the script threaded);
  
  
• by having cron call a simpler Perl script, hourly or daily, which makes use of the supplied modules.

1.1. Data-Collection Modules

• A set of modules each of which supplies a means of getting data relating to a particular system feature, e.g., processes or disk-usage from the system, and scanning it for problems (see _Modules/*).
  
  
• These modules informally divide into two types: those for monitoring (e.g., Mon_Hardware) and those for collecting statistics (e.g., Stats_Disk_Usage).
  
  
• Some of the supplied modules scan standard SysLog files for problems.

1.2. Syslog Message Scanning Modules

...

1.3. Module Output Streams

• Each module has its own set of output modes/streams including: to local file, to remote file, via HTTP and via SMTP (not all yet implemented); see _Mods_Out/*.

1.4. Application Output Streams

• There are five output streams provided for an application script to use. First, three streams intended for monitoring the operating system (and hardware): ticker, warning and trouble. Secondly, log and error, intended for monitoring what the application script itself is doing. (See App_Output_Streams and App_Outs_Config.)
• Several output stream types exist, including: email, FIFOs, on-disk output buffers and events (see _App_Out_Mods/*).

1.5. Applications/Daemons

A simple application script — symon, SyMon.pm — is provided. This is a single-threaded script in which an event-loop calls each used module after its configured interval, and which sends output to the ticker, warning and trouble application output streams.

1.6. Clients

A proof-of-concept script for providing a Web-based monitoring client, wsymon, is also supplied. Alternatively, multitail makes a lightweight but excellent monitoring client!

1.7. System Abstraction Layer

There is a system-abstraction layer, provided by LocalConfig.pm, in which code which is host and/or operating-system-dependent lives.