An anonymous Facebook employee has revealed that all user activity on the site is recorded and stored with as many as six copies of each photo retained.
In an interview on the therumpus.net, the employee answered a question about if everything is saved, whether or not it has been deleted or untagged. He said that was essentially correct, and it was only changing that for performance reasons.
The employee said: “How do you think we know who your best friends are? But that’s public knowledge; we’ve explicitly stated that we record that. If you look in your type-ahead search, and you press ‘A’, or just one letter, a list of your best friends shows up. It’s no longer organised alphabetically, but by the person you interact with most, your ‘best friends’, or at least those whom we have concluded you are best friends with.”
The employee admitted that the change was made ‘sometime in the last three months’, but it stores snapshots, which is basically a picture of all the data on all of the Facebook servers. The employee said that this is done every hour, of every day of every week of every month.
When asked if this is every viewable screen, the employee said: “It is way more than that: it’s every viewable screen, with all the data behind every screen. So when we store your photos, we have six versions of your photos. We don’t store the original: we make six different versions on the photo uploader and upload those six versions.”
These are stored in four data centres around the world – in Santa Clara, San Francisco, New York and London. The employee said that in each of those, there are approximately five to eight thousand servers.
Read more at: SC Magazine UK
