There's a discussion today at Slashdot about how many servers or users an admin can manage. The question seeks to establish whether a department in which sysadmins each manage 900 user machines is understaffed. As in any discussion of IT or data centers, practices vary widely. But here are a couple of relevant factoids from our travels tracking the data center industry.
Jeff Rothschild, the vice president of technology at Facebook, said in a recent presentation that Facebook has 230 engineers supporting data for more than 300 million users. He says Facebook seeks to maintain a ratio of one engineer for 1 million or more users. Facebook is vague about exactly how many servers it has, saying it's "more than 30,000." But 30,000 servers and 230 engineers works out to a ratio of about 130 servers per admin.
Microsoft says it has automated its data center operations to the point where its admins can each manage between 1,000 and 2,000 servers. That matters, as the company may pack more than 300,000 servers into its new container data center in Chicago. It expects to support that facility with about 30 employees, including admins and facility maintenance staff.