“It’s important to be able to monitor your production
system’s health. You want to monitor the memory and file system
utilization, the system load, how much memory the processes use.
Whether you aren’t running out of swap space and more. All these
tasks are feasible when one has an interactive (telnet/ssh/other)
access to the box the web server is running on, but it’s quite a
mess since different Unix tools report about different parts of the
system. Which means that you cannot watch the whole system at
the same time and it requires lots of typing since one has to
switch from one utility to another, unless many connections are
open and then each terminal is dedicated to report about something
specific.”
“But if you are running mod_perl enabled Apache server, you are
in a good company, since it allows you to run a special module
called Apache::VMonitor which provides most of the desired reports
at once.”