STORAGE SYSTEM, STORAGE CONTROLLER, AND METHOD FOR MANAGING MAPPING BETWEEN LOCAL ADDRESS AND PHYSICAL ADDRESS

摘要

According to one embodiment, a mapping manager of a storage controller changes a first chunk from a second state to a third state if an access condition to the first chunk is a first condition that needs high speed access and the first chunk is in the second state. The second state is a state in which a first logical address of the first chunk is mapped to a first physical address in a second storage device slower and having a larger capacity than a first storage device. In the third state, the first logical address is mapped to a second physical address in the first storage device and also mapped to the first physical address in the second storage device.

主权项

1. A storage system comprising:
a first storage device; a second storage device configured to be slower and include a larger capacity than the first storage device; and a storage controller configured to control access to the first storage device and access to the second storage device, wherein the storage controller comprises
a mapping manager configured to manage to which of a first state, a second state, and a third state each chunk of a first size in a logical unit is set, the first state being a state in which a logical address of the chunk is mapped to a physical address of a physical storage area in the first storage device by a first type of mapping information, the second state being a state in which the logical address is mapped to a physical address of a physical storage area in the second storage device by the first type of mapping information, and the third state being a state in which the logical address is mapped to the physical address of the physical storage area in the first storage device by the first type of mapping information and also napped to the physical address of the physical storage area in the second storage device by a second type of mapping information;an address translation unit configured to translate the logical address specified by a read request or a write request from a host apparatus into the physical address of the physical storage area in the first storage device or the second storage device mapped by the first type of mapping information; andan access controller configured to access the first storage device or the second storage device based on the translated physical address, and wherein the mapping manager is configured to:
monitor an access condition to the chunk for each of the chunks in the logical unit;change a first chunk from the second state to the third state if the access condition to the first chunk is a first condition that needs high speed access and the first chunk is in the second state;change the first chunk from the third state to the first state if the first condition continues after the first chunk is changed from the second state to the third state; andchange the first chunk from the third state to the second state if the access condition to the first chunk changes to a second condition that does not need the high speed access after the first chunk is changed from the second state to the third state.