Lawrence Berkeley National Laboratory

Data centers are an important part of modern society, and most computer servers in these facilities are active and productive in storing, processing, and transmitting data. However, some are “zombies”. There are quite a few definitions of zombie servers, but a common thread is a server that consumes electricity but serves no useful purpose. That seems to encapsulate with a few words what a zombie does and does not do, although it still leaves room for interpretation. A zombie server, also known as a comatose or a ghost server, is often, but not always, a server that runs at very low utilization. Not only physical servers can be zombies, but also virtual servers. This document guides the important task of identifying zombie servers.