What Does Lurking Server Mean?

A lurking server is a piece of hardware that may be in an existing architecture, but does not get a lot of attention. In many cases, lurking servers show up after being disregarded for a while, as a result of scaling processes where the company keeps building onto a hardware setup without really taking stock of what is already there.

Techopedia Explains Lurking Server

In the world of network virtualization, the issue of lurking servers remains a challenge. Companies may scale up quickly to get a certain level of performance, but they might not be getting optimized performance out of each individual server. In some cases, lurking servers are carrying obsolete software, which is why they were initially passed over in the first place.