Server monitoring tools - are you overspending on it infrastructure?
Many organisations have over spent on hardware without realising it. About a year ago I looked into proper server monitoring tools, and of course being Linux servers I wanted to monitor I found some very capable free open source solutions. First is munin, which runs over a web interface, but has standalone server which means you can monitor Apache, along with mail services and any other services you may need to keep an eye on. It also emails when a service restarts or dies. Using an email server like postfix it is possible to send a text message alert by piping the email content through a Perl script and sending SMS (this does require an online service that has an API for Perl, I have used the o2sms package, which in Ireland covers all the cell networls). Also it is posssible to monitor server via a WAP gateway for munin to allow us to check and restart services and server status when an internet connection is not otherwise available.
Another nice piece of software is monit, which generates reports on just about every aspects a sys admin would need to know about a system, CPU, disk usage, tasks, mail queues and a host of other useful tid-bits along with a full historical graphing for most too...this can easily identify bottlenecks or under usage of server resources. In particular it is useful for monitoring mail queues and mysql queries which can be stress points from time to time.
Plenty of details on setting these up and getting started can be found on howtoforge.net