You probably want to make sure your websites are up, especially your personal and corporate site. Of course you want all your Rails apps to be up all the time as well. It is a 24-7 world we live in after all. Also it will help you monitor your hosting company and let you know if you’re on a bad server or if you should switch companies completely.
So how do you do that? I recommend two options which I personally use. I’m sure there’s plenty of others, so please leave a comment if you’ve had a good or bad experience with website monitoring services.
The first is Montastic. It’s free and built in Ruby on Rails. It will send you an email whenever your site is unreachable and then another email whenever your site is up again. You have to look at both emails to figure out your downtime manually. The site itself is very friendly and you can point it at any URL on your site.
The second is Uptime by OpenACS. It is very similar to Montastic but has a very plain web interface. It also gives you an email on server down and another on server up, but it calculates the downtime for you. You can point it to any URL, but that URL has to return “success”.