The Disappearing Edge
Oct 7th, 2008 by Clint Eschberger
Server Virtualization started simple enough - a way to consolidate multiple application servers to a single physical host. We might say it was learning to walk before running. At first we saw a move of test and development applications making the move to reduce costs and footprint. Over the last few years however we’ve entered the running phase with increasingly more production systems moving onto hypervisors like VMware and Xen. However for the most part this has been applications and functions that are generally considered to be on the “edge.”
Edge servers are generally considered to be those applications or functions that are “simple” and not business and/or mission critical. This could be anything from file and print servers to simple applications serving departmental functions. Applications that will, in general, not cause any serious impact to the business one way or the other.
So the line of thought has always been that these servers do not need high availability or disaster recovery. This was true! However as true as it may be that only minimal impact may be felt by the business if one edge application goes down, what happens when you have 20-30 edge applications on a single server via a hypervisor? It is kind of like an old saying “a single sting from a bee hurts, but a thousand can kill you.” So even if it was true in the past that you could lose a server, now wither a server running possibly 30 edge servers, that can, and more than likely will, affect the business.
Most businesses have been so busy over the last few years consolidating their data centers that they have moved from what were simple edge servers to a consolidated environment. This effectively moved them into a business critical space. This isn’t a bad thing, but it needs to be planned for and for the most part, it’s been overlooked.
With more and more servers moving onto consolidated platforms, the more we’ll see a need to move to a more dynamic data center model overall. It’s the natural evolution of virtualization after all. The edge is disappearing right before our eyes.
Interesting thoughts. We have found that this is actually quite true and painfully so. We had a 18-1 ratio on VMware and since it was not “critical” servers running on the servers we did not plan for HA or DR. Well when one of the servers crashed we found that 18 “non critical” servers can really hurt more than any one of the guest servers failing. Needless to say we have changed our line of thinking.