We study the design of interactive video servers consisting of disk arrays. In order to avoid the hot-spot problem in video servers its conventional wisdom to stripe the videos over the disk array using Fine Grained Striping or Coarse Grained Striping techniques. Striping, however, increases the seek and rotational overhead, thereby reducing the throughput of the disk array. Our results indicate that the decrease in throughput is substantial when interactive delays are constrained to
be less than 1 second. We show that both a high degree of interactivity and high throughput are achieved by using a narrow striping width and replicating the videos according to the user's request pattern. Specifically, we find that striping over two disks gives the highest throughput when a tight 1 second constraint on interactive delays is imposed. We also demonstrate that localized placement (i.e., no striping at all) performs nearly as well when a good estimate of the user request pattern is available.
