Benchmark: number of servers per adminstrator

Does a thumb rule exists for “server administrators to a number of servers for a large and distributed enterprise infrastructure.”

I know this cannot be applied in every situation, but is there some reference than can be used to derive a head count for 24×7 support operations.
Answers:

1) check out the paper: “How Many Administrators are Enough” http://www.verber.com/mark/sysadm/how-many-admins.html

2) If there is a remote mangement tool to access the same. then the number is around 200-300.
if no software is present and physical present is required, then not more than 50-100 servers per server administrator. I am assuming these servers to be windows servers.
in case of Unix boxes, more servers can be managed even without management software, as patches to be applied are less often and they hardly need to be rebooted. so zero admin scenarios can exisit with unix boxes.
3) Administrators vs no. of servers depends on the stability of the organization and the stability of the OS being used. I have driven an initiative where I could drive the ratio from 150 per SA to 900 per SA. This involved a lot of standardization on the OS level as well as a focus effort to reduce known problems and working on eradication of the problems rather than break fix efforts. A lot of focus was also driven on the quality and training of the SA’s.

Source: LinkedIn Answers (March 2008) http://www.linkedin.com/answers/hiring-human-resources/staffing-recruiting/HRH_SFF/184490-5730787?browseCategory=&goback=.ahp

Benchmark – security breaches

in financial and tech services, almost 40 percent of  security breaches came from the inside, much more than in other groups.

Source:‘Data Breach Target: Your Company’, CIO Magazine, October 6, 2008.

Benchmark – Data Center Staffing and Energy Usage

Microsoft will staff its 500,000-square-foot Chicago data center with only 35 people. Read more about Microsoft’s new data center.

Source:‘How to Staff Your Next Data Center’, CIO Magazine, June 10, 2008.

Data centers built for today’s equipment range from 150 to 300 watts per square foot.
Source: ‘The 5 Pitfalls of Data Center Consolidation and Relocation”, CIO Magazine, November 19, 2008.

Benchmark – cost of bandwidth

YouTube paid $10-15/megabit
Bechtel paid $500/megabit
WHAT BECHTEL LEARNED: It was more than volume discounts from telecom vendors that got YouTube its lower costs. YouTube locates its data centers in places where there’s already a lot of bandwidth, so they don’t have to pay as much for infrastructure.

Source: Bechtel’s New Benchmarks’, CIO Magazine, October 24, 2008

Benchmark – number of system adminstrators per server

Google employs one systems administrator for about 20,000 servers.

Bechtel employed one systems administrator per 100 servers.

Source: ‘Bechtel’s New Benchmarks’, CIO Magazine, October 24, 2008