Posts Tagged AWS Outage

Amazon Outage – Works As Designed

On Sunday 7 August an AWS datcentre in Dublin was taken out by the ultimate act of God – a lightning strike that wreaked havoc on power supply. There is something satisfying about lightning being the cause – it is far easier to picture explosions and blue arcs of electricity as a cause for outage than a badly upgraded router.

News spread faster than it should and the enterprise vendor sponsored media spread their usual FUD about the reliability of cloud services, pointing knowingly to the outage in April as an example of the risks of the cloud.

The key aspect about this outage is it only affected one availability zone in the EU region. The others (two) remained operational. We should be happy that not only doesn’t lightning strike in the same place twice, but, more importantly, that AWS has separate power supplies (and lightning conductors) for each AZ.

Those sites that have been affected shouldn’t tweet about the impact that the outage has had on the systems. They should instead keep quiet and hang their heads in shame. The first principle of building available services in AWS is to make use of multiple AZs and a failure in one should not impact the availability of the application.

There is no news here. A datacentre was struck by lightning and applications that were designed for failure happily continued to run in the available AZs. There is no massive cloud failure here, just a reminder of how things should work.

Update: The report of the outage from AWS is here

Simon Munro




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