Mission-Critical Versus Non-Mission-Critical Applications
It's important to distinguish mission-critical (24x7) versus non-mission-critical (9x5) support. This separation is always controversial, but necessary. It's controversial because people argue that in the client/server world the desktop is just as crucial as those big data center servers housing the applications or database.
I happen to agree, but this issue needs to be put to bed once and for all.
If a single desktop or even a LAN goes down, some people might be inconvenienced for a while, but it won't break the bank. If a mission-critical server goes down, however, it affects hundreds or even thousands of users. And enterprise systems for HR, manufacturing, etc. usually are mission-critical. Systems requiring round-the-clock support need to be branded mission-critical. Mission-critical support means that crucial processes require a specialized group such as production control to implement and maintain them. Basically, the 24 x7 group is paid not to sleep. Their life should revolve around the infrastructure. When a server goes down, the on-call support staff jumps. The 9x5 group is equally important, but is not on call 24 hours a day/7 days a week. The specificity of mission-critical applications varies from company to company. For example, some businesses may require 24x7 support for email.