True, I monitor mine at 5 minute intervals, which I feel makes the report fairly accurate. If you're monitoring at 1 hour intervals and your server is down for 5 minutes when it goes to check, I'd imagine it counts that as an hour of downtime.
We use the system we developed, and was used by NTT/Verio's Enterprise division (January 2001 through late 2003 before they brought the system in-house).
Because it was developed with a data center and enterprise customers in mind, it has an extremely low false positive factor (in three years of operation, we had only two false positives).
Granted, it is our baby, and we are biased; but, I personally love the escalation chains where by different distribution lists can be notified above and beyond the initial alert if a problem has continued beyond a certain point.
I developed a small application in VB.net Win32, runs in the background and monitors each server and multiple services, it can scan in any interval based upon what is supplied. When a service goes offline it has several options (send email, play sound file, do nothing). It also monitors uptime on each server, and can produce a detailed report at the end of the month. I was going to release it to the public as freeware, however I need to make it pretty before I do that
Originally posted by greg1024 Get NetSaint. Search for it on Google. You'll find it. I believe it's the best. You can do lots of cool things like configure it to page you if a server is down and stuff like that.
And, yes, I don't see any reason why it wouldn't work for a reseller!
NetSaint is Nagios. And you need root access to install Nagios...
I recommend getting Alertra 1 Minute Intervals on HTTP. This will let you know when HTTP goes down and will also serve as an excellent way to prove your uptime to your customers. This works for a reseller, too.
Then install SIM from r-fx.net. SIM allows you to recieve alerts when any services go down. It will also alert you when the server load gets too high, etc. It will try to restart downed services and can even be set to stop certain services if the load gets too high. Unfortunately, this requires root access to the server for installation, so would not work for a reseller.
I recommend siteuptime as well. It too can let you show to your clients your uptime (and since it's from a third party it would tend to be a little more reputable then something your home grown system shows). It is free, but if you are willing to pay for it, you can get up to 5 minute intervals on the time checking. It can also alert 2 email addresses. I send an alert to an off-site email account and to my phone.