The figure 4.6 shows the hits per second which measure the number of HTTP requests made by users to the Web server during each second of the load test scenario run. The low percentage of Hits per Second means the fewer requests the application can handle per second.
A virtual client can request an HTML page, image and file, testing the web server for Hits per Second will tell you if there is a possible scalability issue with the application. For example, if the stress on a web server increases but the Hits per Second do not, there may be a scalability problem in the server.
It is worth noting that Hits per Second relates to all requests equally. Thus, a request for a small image and complex HTML generated on the fly will both be considered as hits. It is possible that out of a hundred hits on the application, the application server actually answers only one and all the rest were …show more content…
At any given time, the CPU is either executing programs, user programs or system programs, or it is idling. When it is idling, the CPU is still running, but it is doing nothing useful. A CPU which is idling does not consume the same amount of power that a CPU which is executing programs does, but it generally consumes a significant percentage of that power, typically between 50 and 60%, this will cause a performance degradation for the cloud data center servers.

The figure 4.11 shows the increase in power consumption due to the low server utilization and the power wasted during idle periods as shown in figure 4.11, at any given time, the CPU can be in one of two power consumption modes; it is either executing programs, and in this case it will consumed 100% of its rated power, or it is idling, and in this case it will consumed a significant fraction of its rated peak