A customer is considering migrating their existing non-EMC storage arrays to an XtremIO array. The current environment consists of 350 servers running VMware ESXi 5.5 with 5000 virtual machines. The customer has various tools in place to monitor performance and collect statistics. On average, their service time is 32 ms and utilization is at 75%. In the past, the customer has had performance issues. Based on Little's Law, what is the calculated response time on the existing environment?

Question

Quizplus · Accepted Answer

Little's Law states that the average number of items in a queuing system (L) is equal to the average arrival rate (λ) multiplied by the average time an item spends in the system (W), or L = λW. Given the service time of 32 ms and utilization of 75%, the response time can be calculated as service time / (1 - utilization), which is 32 ms / (1 - 0.75) = 128 ms.

A Customer Is Considering Migrating Their Existing Non-EMC Storage Arrays