The Uptime Institute has estimated the gains from eliminating 'zombie' servers versus doing nothing.
Killing zombies has been a popular theme for teenagers and young adults for years, but the notion appears to be gaining ground among the data center IT operations professionals as well. If zombies can be identified, eliminating them can result in a big savings for the IT budget and a gain in stature for the managers who pulled off the move.
It's been time consuming in the past to track down servers no longer in active use but still running. According to research done in 2015 by Jonathan Koomey , a research fellow at Stanford University and cited by the Uptime Institute, as many as 30% of running servers may be comatose or among the data center equivalent to the walking dead.
The difficulty of tracking little used, aging applications and the tendency of shadow IT users to create new virtual servers and forget about them has contributed to an uptick in the existence of zombies. They exist in nearly every enterprise data center, whether on premises or off in the cloud, according to the research. Any server that hasn't been used to produce useful data or application results in the last six months should be described as a "zombie," the institute said in a summary of its findings.
While the research said the virtual machines could be located either on premises or in the cloud, it offered no results that stated what percentage of zombies might be found in the cloud or whether that portion of the zombie population was increasing.
Still, such servers are a major contributor to what Gartner refers to as the 80:20 split in the IT budget. Historically, 80% of the budget has gone to maintaining existing systems and 20% to creating new business applications. By addressing the zombie server issue, IT managers have a shot at reducing the maintenance side of the ledger and applying the savings to increased investment in new systems.
The research establishing the existence of zombie servers has been cited previously by contributor Ben Kepes in Forbes  magazine in June 2015 and by the Anthesis Consulting Group . The Uptime Institute, a publisher of research on improved data center operations and continuous uptime, was acquired by the 451 Group, a technology market research organization, in 2013.
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