| 摘要 |
Disclosed is a storage system which positions data across tiers while also taking into account sudden changes in loads in short periods so as to improve data hit rates at high tiers. This storage system manages a first access frequency which is a frequency of access from a host device during a first interval, and a second access frequency which is a frequency of access from the host device during a second interval which is shorter than the first interval. Repositioning of data across tiers is carried out at a first interval period on the basis of the first access frequency, and a determination on the basis of the first access frequency and the second access frequency as to the necessity of a second repositioning is carried out in synchronization with the access from the host device. The threshold used in the determination of the necessity of the first repositioning differs from the threshold used in the determination of the necessity of the second repositioning. |
