Web applications rarely stand alone. The database could be powered by Amazon Web Services. Status updates may be fed to Twitter. Your payment system is perhaps just a skin on top of PayPal. Guaranteed availability and service level agreements are fast becoming mandatory.

Just because your providers guarantee availability doesn't mean that they are providing it. Tracking their service level helps you in further negotiations and also helps you find trouble spots with your own application.

Beware the magical numbers!

Many service level agreements contain guarantees which the provider simply doesn't measure, or is incapable of measuring. Several even quote values beyond what they are capable of achieving. Entering into contracts with mythical numbers is very risky.

Please ask for our assistance⇛ in designing appropriate metrics and implementing the appropriate monitors.