Facebook will move older pictures and back-up photos to new-more energy efficient-data centers, called "cold storage" centers. ... the new "cold storage" centers-which are still in construction-will be five times more energy efficient and will allow users to access old images anytime without noticing any difference.Facebook's problem is that they are ingesting 315M photos/day, or 7PB/month. Reducing the energy consumed by the backup copies and the older, less frequently accessed pictures is important. Although this is a work-in-progress and Facebook isn't talking about some details, it appears that among the techniques they are using are erasure coding, to operate with a lower replication factor, aggressively spinning down disks, using flash to hold indexes, and perhaps new, low-power drives such as these from Seagate, which claim 27% less power draw. They are working in the context of the Open Vault project, so this technology should eventually be available to others.
Tuesday, February 26, 2013
Facebook's "Cold Storage"
Last week Facebook announced they are building a couple of "cold storage" data centers: