BBC News – The hum that helps to fight crime
‘Dr Harrison said: “If we have we can extract [the hum of the mains AC power’s 50Hz wave] and compare it with the database, if it is a continuous recording, it will all match up nicely. “If we’ve got some breaks in the recording, if it’s been stopped and started, the profiles won’t match or there will be a section missing. Or if it has come from two different recordings looking as if it is one, we’ll have two different profiles within that one recording.” In the UK, because one national grid supplies the country with electricity, the fluctuations in frequency are the same the country over. So it does not matter if the recording has been made in Aberdeen or Southampton, the comparison will work.’
Two Sides For Salvation « Code as Craft
Etsy’s MySQL master-master pair configuration, and how it allows no-downtime schema changes
(tags: database etsy mysql replication schema availability downtime)
GMail partial outage – Dec 10 2012 incident report [PDF]
TL;DR: a bad load balancer change was deployed globally, causing the impact. 21 minute time to detection. Single-location rollout is now on the cards