Christopher J. Buckley

A common problem faced by a webmaster is, how do I accurately monitor my website’s availability?
This website, for example, has both internal and external health monitors dedicated to achieving high-availability.

Internal

This site’s traffic manager performs a HEAD request for /blog/ every 5 seconds, and makes sure a valid HTTP status code is recorded. This is done through a simple regex of ^[234][0-9][0-9]$.

Further, health monitors ‘ping’ and ‘TCP connect’ are enabled to make sure a) the box is up b) the desired socket is able to receive connections.

External

So, we’ve got good internal monitors in place. But how do we check on the availability/performance of our site over a WAN? Two sites I have knowledge of and can recommend are:

• Site Confidence monitor website performance for many of the UK’s largest companies, including many well-known brands and businesses such as; Norwich Union, Auto Trader, Marks & Spencer, John Lewis, First Choice and Experian.
• HostTracker is a free-to-use service, with 52 different testing nodes in Europe, The Americas and Asia.

The beauty of the services above is that they allow you to input POST form data; this allows a webmaster to perform a transaction against his service - remotely. If you stop transacting, it’s best you know first, rather than your customers ringing up to complain.