Hot weather, toasty hosting
posted 27th June 2011 | by Xagga Hosting
Today the UK had its hottest day of the year so far – yay! Temperatures reaching up to 32°C in parts of the UK (possibly more, but the MET office web site isn't all that helpful). Hot weather is certainly a novelty for the UK, and is bliss for most of us – but some data centres and web hosts haven't been all too happy…
With scorching hot temperatures on the outside, then plenty of high-spec power-guzzling heat-generating monster servers on the inside, obviously data centres are gonna heat up. That's fine; redundant air conditioning systems are put in place to take care of that. But what if your hosting provider's data centre is oversold, or cutting costs? Well, the big F word crops up, and that's exactly what happened in some southern data centres today – they Failed.
I'll just take a second to explain to you all how data centre cooling setups are designed to work.
Typically, inside the data centre you have server racks set up in a 'warm aisle' and 'cold aisle' environment. A 'cold aisle' has two rows of servers facing inwards (sucking cool air through their front vents). Cold aisles are cooled between 20°C and 24°C respectively, dependant on the data centre. Then you have your 'warm aisle' where the back ends of two server racks blow their hot air which is then extracted and/or cooled.
Air is cooled and filtered by large chillers outside of the data centre building, which deliver very cold liquid to fan coolers in the 'cold aisle' of the data centre floor. Most data centres expell their cool air via fan coolers at either end of the 'cold aisle' though some data centres have dedicated venting in the flooring for this.
But what happens when the ambient air that the chillers suck in the hot ambient air of summer days like today? Well, their output product – that normally cold liquid feeding the coolers in the data centre – becomes warmer. I'm sure you can work out that warmer air being fed in to the cold aisles unfortunately gives you warmer servers, which then ensures warmer ambient data centre temperatures that the chillers fail to manage. Going round in a vicious circle, unless the outside air becomes cooler or the servers generate less heat, the data centre's ambient temperature continues to rise. This is where the Fail comes in to it.
The UK has average temperatures of 5°C in Winter and 18°C in the summertime, thus data centres are designed with those figures in mind. When we have a day like today, with 32°C+ peak temperatures coupled with a night like last with 18°C average minimum overnight temperature, data centre cooling setups are pushed to their limits.
I'm not sure how much you know about the costs of housing equipment in data centres, but it's far from cheap! For the price that hosting providers pay to host their equipment, they would expect data centres to have more-than-adequate cooling for all equipment, and for all extremes of weather. Sure, with today's heat one would expect slightly warmer data centre ambient temperatures, but some data centre ambient temperatures rose to almost peak outside temperature (30°C). This is completely unacceptable, and obviously causes very expensive equipment to fail.
Thankfully, Xagga Hosting's primary facility stayed well within its thermal limits and we had no mishaps. +1 for us, pat on the back time!
