Tiered storage system provided with trial area, storage controller, area allocation method and storage medium

摘要

According to one embodiment, a tiered storage system includes a high-speed storage device, a low-speed storage device, and a storage controller. The storage controller interchanges a location destination of data of a first logical chunk to which a third storage area of the low-speed storage device is allocated and a location destination of data of a second logical chunk to which a first storage area of the high-speed storage device is allocated and whose access frequency statistical value is smaller than that of the first logical chunk. The storage controller reallocates a second storage area of the high-speed storage device to a set of logical chunks to which the third storage area is allocated.

主权项

1. A tiered storage system comprising:
a first storage device comprising a storage area including a plurality of physical chunks each having a first size; a second storage device comprising a storage area including a plurality of physical chunks each having the first size, the second storage device having a lower access speed and a larger storage capacity than the first storage device; and a storage controller configured to control the first storage device and the second storage device, and comprising a logical volume management unit, an access statistical collection unit, a first rearrangement unit, a second rearrangement unit and an evaluation unit, wherein: the logical volume management unit is configured to manage a logical volume to which a first storage area of the first storage device, a second storage area of the first storage device and a third storage area of the second storage device are allocated in units of physical chunks, the logical volume including a plurality of logical chunks each having the first size, and being provided to a host computer; the access statistical collection unit is configured to collect access frequency statistical values indicative of states of accesses to the plurality of logical chunks in the logical volume, respectively; the first rearrangement unit is configured to:
select a first logical chunk whose access frequency statistical value is great; andreallocate a second physical chunk in the first storage area to the first logical chunk and reallocate a first physical chunk in the third storage area to a second logical chunk, if the first physical chunk is allocated to the first logical chunk before the reallocation of the first physical chunk and the second physical chunk is allocated to the second logical chunk before the reallocation of the second physical chunk, and if the second logical chunk has an access frequency statistical value smaller than that of the first logical chunk; the second rearrangement unit is configured to:
sequentially select a plurality of sets of physical chunks in the third storage area, regardless of access frequency statistical values of logical chunks included in a plurality of sets of logical chunks to which the plurality of sets of physical chunks are allocated;in accordance with selection of one of the sets of physical chunks, reallocate a third set of physical chunks in the second storage area to a set of logical chunks to which the selected one of the sets of physical chunks has been allocated; andreallocate a second set of physical chunks in the third storage area to a second set of logical chunks, when a first set of physical chunks in the third storage area is selected as the one of the sets of physical chunks, and if the third set of physical chunks in the second storage area is reallocated to the second set of logical chunks before the first set of physical chunks is selected and the second set of physical chunks is allocated to the second set of logical chunks before the third set of physical chunks is reallocated to the second set of logical chunks; and the evaluation unit is configured to:
execute at least one of a random read access to the logical volume and a sequential read access to a fourth storage area of the logical volume in accordance with reallocating the third set of physical chunks to the set of logical chunks to which the selected one of the sets of physical chunks has been allocated;measure a throughput of the at least one of the random read access and the sequential read access; andacquire the measured throughput as an evaluation result obtained by reallocating the third set of physical chunks to the set of logical chunks to which the selected one of the sets of physical chunks has been allocated; and the second rearrangement unit is further configured to reallocate the third set of physical chunks in the second storage area to a first set of logical chunks when a throughput acquired by a first reallocation is the greatest, the first reallocation including reallocating the third set of physical chunks to the first set of logical chunks when the first set of physical chunks is selected as the one of the sets of physical chunks, the first set of logical chunks being a set of logical chunks to which the first set of physical chunks is allocated before the first reallocation.