What are IOPS & how to calculate?

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IOPS (Input/Output Operations Per Second, pronounced eye-ops) is a common performance measurement used to benchmark computer storage devices like hard disk drives (HDD), solid state drives (SSD), and storage area networks (SAN)

How many of you have seen storage vendors extolling the virtues of their storage by using large IOPS numbers to illustrate a performance advantage?

How many of you decide on storage purchases and base your decisions on those numbers?

Using these online calculators, you can calculate the RAW IOPS as well ACTUAL IOPS

What is an Erlang?

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An Erlang is a unit of telecommunications traffic measurement.  Strictly speaking, an Erlang represents the continuous use of one voice path.  In practice, it is used to describe the total traffic volume of one hour.

For example, if a group of user made 30 calls in one hour, and each call had an average call duration of 5 minutes, then the number of Erlangs this represents is worked out as follows:

  • Minutes of traffic in the hour =             number of calls x duration
  • Minutes of traffic in the hour =             30 x 5
  • Minutes of traffic in the hour =             150
  • Hours of traffic in the hour =             150 / 60
  • Hours of traffic in the hour =             2.5
  • Traffic figure =             2.5 Erlangs