I believe that the CIA had a supercomputer cluster that was running map reduce jobs using Apache Corona. Internally they probably talked about CORONA as a shorthand for the analysis jobs that ran on that system. So, when Q dropped that CORONA was deactivated it meant that the whitehats had taken control of the data centers (plural) in which the CORONA cluster was located.
The way that type of cluster works is that a job is allocated to whatever computers in the cluster are available. Then the cluster is placed in multiple data centers so that a power outage or an Internet outage will only affect a portion of the cluster. Makes it harder to take control because you have to know where all the physical computers are and that could be obfuscated. That's why it is such a big deal to deactivate ity and so Q made note of that.
Mainly that stringer was for the CIA folk listening in who know the implications of losing the Corona cluster because they know what kind of jobs they run on it. Could be facial recognition across many security surveillance cameras. Could be analysis of opponent's actions and recommendations for counter action, what most people call AI but it really is just more computer code. A machine is NEVER INTELLIGENT..