How Multiple Server Hosting impacts your website's uptime by: Godfrey E. Heron
This article describes technology behind multiple server hosting and how you may utilize it to maximize your site's security and uptime.
Hosting of websites has essentially become a commodity. There is very little distinguishing one hosting company from next. Core plans and features are same and price is no longer a true determining feature. In fact, choosing a host based on cheapest price can be more expensive in long term with respect to reliability issues and possible loss of sales as a result of website downtime.
Selecting a host from thousands of providers and resellers can be a very daunting task, which may result in a hit and miss approach. But although hosting may have become a commodity, one distinguishing feature that you must always look out for is reliability.
If you don't know uptime of your site, or its performance level, try a website monitoring service.
At heart of any hosting company's reliability is redundancy. This ensures that if a problem exists at one point, there will be an alternative which ensures continuity as seamlessly and transparently as possible.
Most hosts do employ redundant network connections. These are high speed pipes that route data from server to your web browser. But, redundant 'multiple web servers' have been extremely rare and very expensive, requiring costly routing equipment which has previously been used only in mission critical applications of Fortune 500 companies.
However, a very neat but little known Domain Name Server(DNS) feature called 'round robin' allows selection and provision of a particular IP address from a 'pool' of addresses when a DNS request arrives.
To understand what this has to do with server reliability it's important to remember that Domain Name Server (DNS) database maps a host name to their IP address. So instead of using a hard to remember series of numbers (IP address) we just type in your web browser www.yourdomain.com, to get to your website.
Now, typically it takes at least 2 to 3 days to propagate or ‘spread word’ of your DNS info throughout internet. That's why when you register or transfer a domain name it isn't immediately available to person browsing web.
This delay has stymied security benefits of hosting your site on multiple servers, as your website would be down for a couple of days if something went awry with one server. You would have to change your DNS to reflect your second server and wait days before change was picked up in routers on internet.