What is the optimum number of admins to server? [closed]
I'm starting a business, and I'd like to know what you guys think the optimum number of admins to server ratio is for financial modeling reasons. Or if there's a better metric to use? I come from an embedded programming background so this is an area that I'm pretty squishy on knowledge-wise. : \
Additional Info:
There will be a lot of servers.
Mainly Linux boxes, with about 10% Windows boxes.
Thanks in advance!
Updates from Comments
All I'm asking for is a ballpark figure. It needs to be very high availability, but luckily the system lends itself to spares/replicas.
Three database clusters (two cassandra, one sql) with around a million rows each. About 200 Linux boxes running a custom protocol (but is ultimately just a proxy for the datbases), two SANs with about a petabyte a piece, about 200 Linux boxes as basically video encoding appliances, about 50 windows boxes running the same custom proxy software.
And pay competitively. I'd rather have a few good admins than a lot of bad ones. Any more info needed?
I build platforms and form support teams in a similar manner, plus you state you need 'very high availability (HA)', that's what I do too, so let's see how we get on :)
You need to break your skillsets down into groups, also you're covering a lot of bases here and HA requires good or great skills rather adequate or intermediate skills.
From what information you've given us I believe you need;
4/5 first-line people - these will take calls, monitor operational-status dashboards, perform scheduled routine tasks and fix minor, frequently-occuring problems across all technical areas. You need so many to cover 24/365 with vacation cover.
2 networking people - you need a more junior CCNA-level person and a senior CCNP (or CCIE if you have the budget) level person - they need an on-call rota and will need extra pay set aside to cover this cost and out of hours bonuses.
1 REALLY good SAN person (take experience over qualifications ok), again they'll be on call 24/365 but you also need them to gradually train up a junior to cover them when they're away - consider the more junior network person mentioned above as some of the skills will be vaguely similar to network config work and will keep them keen when they're bored of being told what to do by the more senior network person. Don't let this senior SAN person also be your DB designer, not that they won't be capable of it or contribute a lot but you need a clear demarkation line between the two functions.
2 good or great Linux and DB admins PLUS one REALLY great DB admin with lots of experience, again put them on a callout rota.
Oh and make sure that your 'service manager' is structured, clear in their communications, happy to listen to his team and capable of using the word 'no' - do NOT expect them to directly project manage new additions to your platform (minor changes yes but not large functional additions), get someone else to work project manage these by working with the SM.
Now obviously this is quite a lot of staff, but then again you're asking us for how we'd do this and this is exactly how I'd do it - I'm utterly focussed on serving my business and understaffing/skilling a HA-requiring platform fails to achieve this goal.
There is no such thing as "admins per server". You can not apply "miles-per-gallon" metric here.
It's possible to have 5 smart guys administering a well designed farm of 4,000 servers. It's also possible to have 5 dumbasses not knowing how to administer a single Windows server even though they had all the right acronyms on their resumes.
UPDATE: I am going to expand this answer a little bit.
This job has no consistency. You can be sitting and twiddling your thumbs for 2 weeks with nothing to do, and the next thing you know, you are woken up at 3am and and it turns into a major project that you end up working on for 3 weeks straight 12 hours a day.
But if you are always busy due to something breaking, you are not doing your job right. Companies know that, thats why most of admins are salary. Its much easier for them to pay you salary and have you sit on your ass when everything is working, rather than paying hourly and overtime when you have to fix something 24x7.
What I am saying is that you can not put any measurement on this job, beside man-hours for payroll purposes. Make sure you find one solid guy, not just anyone with acronyms on their resume. If you do not know what to ask of him, find some who can help you interview. Pay market. You get what you pay for, especially in this business. Good guys are not cheap. 1 expensive, but solid admin is better than 3 cheap ones without any experience.
Start with 1 guy, but leave room for more.