Sysfence project is a resource monitoring tool designed for Linux machines. While running as daemon it checks resource levels and makes desired action if some values exceed safety limits.

Here are some key features of "sysfence":

· notifying system administrators when something goes wrong,
· stopping services when system performance is dropping too low and starting them when it's going up again,
· periodically restarting memory-leaking processes,
· dumping system statistics in critical situations



Usage

Sysfence reads it's configuration from file(s) specified in argument list. Config files may contain one or more rules describing conditions and actions to be performed.

Rule has syntax like this:

if {
resource1 > limit1
or
{ resource2 < limit2 and resource3 < limit3 }
}
run once 'command-to-be-run'

The block enclosed within {} brackets describes condition. When it's result is TRUE, following command is invoked.

The once keyword is optional. If present, the command is executed only once after condition becomes TRUE. Next execution will take place only if condition becomes FALSE and then TRUE again. Without once keyword, command is invoked periodically, after every resource check that gives TRUE, no matter what was the condition result before.

Command specified right after run keyword is passed to /bin/sh, so it may contain more than one instruction or even whole script. But be careful - rule checking is suspended unless command execution has been completed! (Other rules are unaffected.)

As resources, following ones can be given:

* la1 - load average during last minute.
* la5 - load average during last 5 minutes.
* la15 - load average during last 15 minutes.
* memfree - lower limit for free memory amount.
* memused - upper limit for memory used by processes.
* swapfree - lower limit for free swap space.
* swapused - upper limit for swap space in use.

What's New in This Release:

· This release contains bugfix for wrong memory levels recognition on non-vanilla kernels.