“We have observed that it can be, for example with a physical server, as low as 10 per admin, and for virtual servers as many as 500,” Gartner analyst, Errol Rasit, said. “But it really depends on the type of application. We have seen as an example from a particular customer – from some of our larger customers – that they had their admins managing 15 physical servers and when that moves to virtualisation it moves to something like 75 virtual servers.
To give you a different order of magnitude in another example one admin was looking at 50 physical servers and then moving to 250 virtual servers. I will say that we have seen maybe 500 or 600 virtual servers being managed by a single admin.
IDC meanwhile notes that in Australia the ratio for an SMB would vary greatly from a hoster and again to a cloud provider like Amazon or Microsoft. The analyst house’s statistics suggest anywhere from 10,000:1 at a dominant vendor like Google down to the SMB average of 30:1 for physical boxes and 80:1 for virtual machines.
One enterprise IT manager told us the ratio for physical servers was roughly 50:1, another working for a government organisation said 15-20:1, and an IT director at a research and development outfit noted that in a mid-size organisation a system administrator could maintain 10-14 servers per week or if their role was merely maintenance (i.e. no projects, no debugging, etc) then they could look after 25-35 servers per week. The IT director added a bigger organisation with larger economies of scale could potentially increase the ration to 10-14 servers to each admin per day with staff dedicated to just maintenance.
One of the key factors in increasing the ratio, however, is how much automation can be rolled into the maintenance / management of the server farm.
“A lot of what changes the ratio in the physical world is the types of tools being used to automate a lot of the processes; so run book automation and these sorts of things,” Gartner’s Rasit said. “That tends to be the main differentiator. The problem with virtualisation and virtualisation tools is there are a lot of them. It is very, very easy for a lot of customers to try and automate everything and that doesn’t necessarily always bear fruit for the organisation because they are spending too much time doing that.
A complete copy of the article can be found: http://www.computerworld.com.au/article/352635/there_best_practice_server_system_administrator_ratio_/