Sometimes it’s necessary to take your site totally offline – but it can and should be done in a Google-friendly way.

It’s not uncommon in the scenario of site maintenance needing to be done for a 301 or 302 redirect to be used to point to a page explaining why the site is down – after all, it’s pretty simple to do.

The problem with this is that 301 and 302 redirects tell Google specific things:

301 – page has moved permanently
302 – page has moved temporarily

Neither of these are correct when maintenance is being carried out and they also give Google the wrong message that

consequently can impact on rankings; even if you’re in maintenance mode for a reasonably short time.

Another method sometimes used is to 404 all pages – 404 means “file not found” – again, not correct and can also cause

ranking headaches.

There is a specific error code that should be returned in maintenance mode – 503

Basically, a 503 code says:

“The server is currently unable to handle the request due to a temporary overloading or maintenance of the server”.

Perfecto – exactly what you want. Google and other search engine robots understands what this error code means.

Yoast has some info on how to send a 503 header in PHP and 25YearsOfProgramming also has some good examples using .htaccess (but steer clear of the 307 suggestion IMO – stick with his 503 examples).

SEOMoz also has an in-depth article on how to handle downtime during site maintenance.

Even if you don’t have time to read any or all of the above tutorials, at least bookmark them in case disaster should strike and you need to take your site entirely offline.