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Your OLTP system generates 600,000 physical disk accesses per hour. You have two physical disks on which to place the data files. The fast one takes 5 msec to complete an IO operation, the slow one 15 msec. What fraction of the IO operations should go to the faster disk in order to minimize the mean IO response time?
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The answer to the puzzle.
Load Balancing Puzzle - last updated July 11, 1996