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Black Friday Blues: How to dodge a thankless day's online sales crush
Peaks are not unpredictable. Peaks are NOT unpredictable
Architect it sensibly
It frustrates the hell out of me when cloud providers' salesdroids start banging on with: “Ah, of course the benefit of the cloud is that you can spin servers up and down at will to cope with requirements.”
A lot of the time it's nonsense – particularly when they use my favourite example of the winding up the power of the finance system at year-end and then winding it down again.
But with online stores, it really can work: some nice beefy load balancers at the front end to share the load (they'll have to cope at peak periods, after all), and you really can wind the back-end up and down: script the server management based on load, and configure the load balancers to turn off and on the streams of traffic to backend servers based on whether they're available.
Black Friday (and other peak sales days) is inevitable. We can't really spread dates like Christmas, Easter or Valentine's Day across the year and so we have to live with the skew in sales. We can, however, deal with them by treating the concept as a science rather than an art and taking common-sense steps:
- Analyse the market and historical data and use it scientifically as a prediction tool. There's no hard and fast prediction, but weird spikes notwithstanding you'll generally be pretty close.
- Host your systems somewhere sensible and architect them so they can scale – and exploit the fact that this is one of the few times when the “expand and contract” sales-speak actually does work.
- Ensure that your third-party services can cope with your predicted load.
- Verify and test each component and service to ensure there's no weak link. Remember that the IT is just one part of the equation: if the technology gets hit hard, so will the customer service teams.
Above all, make sure that you do what you can to ensure you don't overload the system – by spreading the marketing campaign if necessary.
After all, there's no point trying for the world record for daily online sales if The Reg writes during the following six months about how crap your systems were on Black Friday. ®