Dixons’ annual sale got off to a bad start this morning when the website went offline due to a “high volume of visitors.”

One of the main aims of a sale is to drive increased volumes of traffic, so the outage suggests that Dixons failed to properly test and prepare its systems in the run up to the event.

And it’s not like the electronics retailer hasn’t had prior warning of this type of issue from other online retailers.

In November Ebuyer.com promoted its ‘Mega Monday’ sale by offering a range of items for just £1 – and its site promptly fell over causing a flood of complaints on Facebook and Twitter.

In 2009 Next implemented an online queuing system to help it cope with sales traffic, while in November 2008 Debenhams’ website crashed twice during a week-long sale.

At the time of Debenhams’ web failure Experian Hitwise estimated that while 33.2% of the retailer’s downstream traffic went to other retail websites on the 18th (the day before the sale) by the 22nd this figure had reached 46.9%.

The main beneficiaries of the crash were M&S, John Lewis and Next who all received additional traffic as a result.

It’s too early to say how much traffic Dixons will be losing traffic to its competitors, but at the time of writing the site had been down for several hours so it’s likely that customers will have started to shop elsewhere as a result.

Following Debenhams’ website crash we spoke to several UK hosting firms to see find out how e-tailers could avoid suffering similar problems.

CEO of DediPower Managed Hosting Craig Martin said that in preparation for sales e-tailers need to predict how much traffic they expect to receive and run load testing to find out how the site will operate during busy periods.

The results will advise how many users the site can cope with before the user experience is impacted and based on the results, the site’s codebase and underlying infrastructure can be adjusted and tweaked to maintain optimal performance during the busy period.

In the event that the site does fall over, there are a number of options open to website owners.

For instance they could use scalable servers for rapid deployment, sophisticated load balancing to off-load traffic spikes or utilise a CDN (content delivery network) to offset the load associated with the delivery of images and video.

At the moment Dixons may be considering all or none of these options as it tries to get its site back online.

But in the meantime, every visitor who sees the error message is a potential customer lost to its competitors.