As per the below screen shot taken from DEV_301 Slide Guide page 40, it is mentioned as 1 queue per cluster. What does it mean?
A queue is basically a "line" where applications wait for resources to run. By default, there is one queue - meaning all applications that run are standing in the same line. It's possible to configure multiple queues, and give the different queues different priorities, different amounts of resources, or preferential treatment.
Think of it this way: you show up at the airport and need to get through security. Most people go into the one big line (one queue) to wait their turn. That's the default "single queue". But at some airports, there are expedited lines for people with pre-established clearance, or for people with First Class tickets. Those are the "good" lines.
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