[CentOS] OT - Monitoring tool

I'm looking for a tool to monitor my servers and send either an email or
page 
or both when something breaks.
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JohnStanley Writes:

Hobbit, Spacewalk (rather new & requires Oracle DB), Big Brother, Zabbix and
many more. It's mainley an admins choice of what he/she wants or needs to
do.

JohnStanley

OT:
ATTENTION: If anyone finds this reply with an html attachment please let me
know. Thanks in advance.