Rise of the machines
Rac Plus, January 6, 2016. Image credit: Dennis van Zuijlekom
In June 2015, a study by Jonathan Koomey and Jon Taylor confirmed the view that a great deal of the servers inside the data centres are just consuming electricity, while not being used or accessed in any way.
The study concluded that the level of these servers, which are called comatose servers, is at 30 per cent of all the servers inside the data centres.
Identifying that the redundant and rarely accessed data in the public cloud comprise a large share, in 2013 Facebook separated the old data into the “cold storage” category.
Cold storage can be defined as the retention of inactive data that an organisation or an individual rarely, if ever, expects to access.
Previously, it was believed to be necessary for the servers in data centres to be “always on” to provide immediate access to users’ data, but the servers in the cold storage facility are on “sleep mode” and kick-start only when there is a request for access to archived information.
There will be a certain delay in accessing data by the end-user, but that slight delay is believed to be acceptable.
Facebook has devoted considerable attention to the hardware used for a cold storage system through the Open Compute Project that has been working on the improvements in the hardware systems used in data centres, including cooling.
It led to adoption of direct evaporative cooling in Facebook data centres and, following some teething problems in 2013, it has been implemented across an increasing number of its storage centres with improved control.