Method and apparatus to manage tier information

A non-transitory computer-readable storage medium storing a plurality of instructions for controlling a data processor to manage storage tier of data, in a system which includes a host, a network, and a storage system coupled to the host via the network, the storage system having a memory, a plurality of virtual volumes, a plurality of logical volumes, and a plurality of types of storage devices being configured for forming at least three levels of storage tiers, each of the at least three levels of storage tiers having a plurality of storage areas, a storage area of the plurality of storage areas being allocated to a virtual storage area of a plurality of virtual storage areas of a virtual volume for storing data in accordance with receiving a write command to the virtual storage area, the plurality of instructions comprising:

• instructions that cause the data processor to manage tier migration log information which includes correspondence between the virtual storage area of the plurality of virtual storage areas and the storage tier of the at least three levels of storage tiers at various points in time, and to allocate the virtual storage area to another storage tier based on a condition of migration whereby data stored to the virtual storage area is migrated from the storage tier to the another storage tier according to a characteristic of the data stored to the virtual storage area;
• instructions that cause the data processor to store the log information for a plurality of restore points corresponding to different levels of storage tiers, and to allocate the storage tier to the virtual storage area based on the log information for restoring the data stored in the virtual storage area to the storage tier allocated to the virtual storage area at one of the restore points selected by a user in a tier restoration to the selected restore point in time;
• wherein the memory stores tier destination information which includes virtual volume name, virtual volume address, capacity, number of access, access per capacity, current tier, and destination tier, that are organized in a descending order of access per capacity;
• and
• instructions that cause the data process or to manage migration of the data stored to the virtual storage area from a current storage tier at a current time to another storage tier at the selected restore point, using the tier destination information and the log information.

A method of storage tier management of data, in a system which includes a host, a network, and a storage system coupled to the host via the network, the storage system having a memory, a plurality of virtual volumes, a plurality of logical volumes, and a plurality of types of storage devices being configured for forming at least three levels of storage tiers, each of the at least three levels of storage tiers having a plurality of storage areas, a storage area of the plurality of storage areas being allocated to a virtual storage area of a plurality of virtual storage areas of a virtual volume for storing data in accordance with receiving a write command to the virtual storage area, the method comprising:

• managing log information which includes correspondence between the virtual storage area of the plurality of virtual storage areas and the storage tier of the at least three levels of storage tiers at various points in time;
• allocating the virtual storage area to another storage tier based on a condition of migration whereby data stored to the virtual storage area is migrated from the storage tier to the another storage tier according to a characteristic of the data stored to the virtual storage area;
• storing the log information for a plurality of restore points corresponding to different levels of storage tiers;
• allocating the storage tier to the virtual storage area based on the log information for restoring the data stored in the virtual storage area to the storage tier allocated to the virtual storage area at one of the restore points selected by a user as a tier restoration to the selected restore point in time;
• storing in the memory tier destination information which includes virtual volume name, virtual volume address, capacity, number of access, access per capacity, current tier, and destination tier, that are organized in a descending order of access per capacity;
• and
• managing migration of the data stored to the virtual storage area from a current storage tier at a current time to another storage tier at the selected restore point, using the tier destination information and the log information.