Strictly System Check is a plugin that periodically checks your site checking your database and server and reporting if any problems are found.
I made this plugin as a basic site monitoring system for WordPress users. Little did I know whole business models would be created around it.
I have lost count of the "site" monitoring tools that are trying to charge businesses and people money for what amounts to basically the same simple monitoring that this plugin does.
It's no joke, I even have a free account with some systems that hourly run a simple HTTP request to a page of your choice and check for the existence of known words in the source and then if they are not found they fire off a "warning" email to a specified email address.
Not only is that a total joke! Why would you pay for something that you could write yourself with a few lines of PHP/C# and a HTTP / CURL request and a stripos call but this plugin actually goes further than these rip off merchants and tries to fix problems if it finds them.
Not only will it report on MY SQL activity, connections, indexes, lookups and so on but if the server is overloaded it will try and fix the system with OPTIMIZE and REPAIR commands if you so wish.
The plugin uses its own configuration files so it doesn't have to load in hundreds of bloated WordPress includes to run. This means if core WordPress code or database connections have been changed or corrupted the plugin will still work due to it having its own configuration file.
How people can make whole business models out of simple HTTP monitoring I don't know but I would suggest for the tech savy out there to set up very simple (publicly non-accesible) sites on the same server (or have access to the same Database) to run your monitoring just in case the site you are monitoring from is down. E.G if the site you are running this plugin from is overloaded then having this plugin on that site will take extra resources (however not as much as other plugins) - therefore ideally a "monitoring" site would be preferable. Maybe even update this plugin to monitor multiple sites at the same time.