As everyone knows, retail is an extremely seasonal industry. Retail E-Commerce is no different so when building an environment to support a retail site, architects and engineers have to plan for the highest demand. Let’s pretend cloud computing doesn’t exist or isn’t feasible in this case.


You’ve got a site that has an average daily peak of 50Mbps but on Black Friday, the peak is 1.2Gbps. Besides Black Friday, no other day of the year exceeds 200Mbps. Naturally ISPs can provide burstable ethernet so you’re only paying for what you use, but switches, load balancers, etc might not provide the same capability. So, you might have to build (and buy) an infrastructure that supports 10 Gbps to provide for your “peak” growth as that 1.2Gbps number might grow at 40% a year or more.


Before building out this environment though, it might be beneficial to learn more about your “peak” demand. For instance, let’s say the peak happens at midnight on Black Friday and that it’s sustained from 12:00 – 12:50 AM. High demand continues the rest of the day, but never exceeds 500Mbps. Why are so many people hitting your site from 12:00 – 12:50 AM? Let’s assume the marketing people tell us that they release some sort of promotion allowing shoppers huge discounts starting at 12:00 AM and going throughout the day. Unfortunately, there’s only enough inventory for 100 of each discounted item, so shoppers hit the site as soon as they’re available.


Before this conversation, we were planning on building an infrastructure to support that 1.2Gbps (and beyond) number that’s only hit once per year, and for only an hour. Now that we know more about why that time period is so popular, it’s time to determine whether it’s “cost-effective.” Let’s say we’re spending $1M extra to support demand that exceeds 1Gbps. If we want to avoid that spend, what options do we have to keep our traffic spikes under 1Gbps? What if the promotions are released the night before Thanksgiving? What if different promotions were released each hour during the day? What if there was enough inventory to assure all customers the items they want? What if promotions were e-mailed to different customers at different times? Obviously a marketing group would be better able to answer these questions than I, but there’s a decent chance that such methods could eliminate the short (duration), large (size) spike. Perhaps rather than a 1.2Gbps spike from 12:00 – 12:50 AM, we see a 500Mbps spike from 11:00 PM – 3:00 AM. Assuming profitability isn’t tied to when folks are buying goods, such a change in traffic spikes would allow us to delay a large expense for at least another year.


Naturally, retail is a great arena for public cloud. What happens, though, when all retailers are on public cloud? Wouldn’t the cloud provider have to have a huge hardware footprint to support Black Friday for all of its retail customers? At any rate, supporting seasonal demand is definitely a challenge, but it poses some interesting opportunities.