CCNA Data Center DCICT 640-916 Official Cert Guide

Before Server Virtualization

Traditionally, you were used to a single application running its own operating system on an individual piece of server hardware. That server consisted of NICs and HBAs; their ports would connect to redundant network access layer and fiber channel switches. Network control security policies, QoS, and so on were created at this access layer switch port level, related to that application’s usage. These policy enforcements were static and very rarely needed any modifications.

If that server required any maintenance or upgrades and needed to be offline, but the application needed to be available, redundancy was built with a cold or hot standby server or host-based clustering, at a cost. Figure 18-1 shows typical server ...