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US 10,095,439 B2Granted
Tiered storage system, storage controller and data location estimation method
AssigneesKabushiki Kaisha Toshiba, Toshiba Solutions Corporation
InventorYasuhiro Ono
Life of this patent
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Abstract
According to one embodiment, a tiered storage system includes first and second storage devices having access speeds different from each other, and a storage controller. The storage controller manages first and second access frequency statistical values. The first access frequency statistical value corresponds to a state in which data of a respective one of logical chunks is located on the first storage device, and the second access frequency statistical value corresponds to a state in which data of the respective one is located on the second storage device. The storage controller determines whether it is necessary to change the location state of the data of the respective one, based on the first and second access frequency statistical values of the respective logical chunks.
Claims17
A tiered storage system comprising:
- a first storage device which comprises a storage area including a plurality of physical chunks having a first size;
- a second storage device which comprises a storage area including a plurality of physical chunks 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 which controls the first and second storage devices, wherein:
- the storage controller comprises a logical volume management unit, an access statistics collection controller, an evaluation controller, an evaluation value calculator, and a relocation controller;
- the logical volume management unit manages a logical volume including a plurality of logical chunks having the first size, the logical volume being provided to a host computer, the storage areas of the first and second storage devices being allocated to the logical volume physical chunk by physical chunk;
- the access statistics collection controller collects, during respective monitoring periods, access frequency statistical values representing statuses of accesses to the respective logical chunks;
- the evaluation controller records a first access frequency statistical value and a second access frequency statistical value associated with a respective one of the logical chunks, the first access frequency statistical value representing a status of access to the respective one of the logical chunks which is in a first location state in which data of the respective one of the logical chunks is located on the first storage device, the second access frequency statistical value representing a status of access to the respective one of the logical chunks which is in a second location state in which data of the respective one of the logical chunks is located on the second storage device;
- the evaluation controller updates, during the respective monitoring periods, the first or second access frequency statistical value corresponding to a location state of data of the respective one of the logical chunks such that the first access frequency statistical value indicates an access frequency statistical value recorded during a most recent monitoring period in which the data of the respective one of the logical chunks is in the first location state and the second access frequency statistical value indicates an access frequency statistical value recorded during a most recent monitoring period in which the data of the respective one of the logical chunks is in the second location state, based on one of the collected access frequency statistical values, which is associated with the respective one of the logical chunks;
- the evaluation value calculator calculates an evaluation value based on the first and second access frequency statistical values of the respective one of the logical chunks, the evaluation value indicative of a degree of improvement of access performance obtained when the location state of the data of the respective one of the logical chunks is changed from the second location state to the first location state;
- and
- the relocation controller determines whether it is necessary to change the location state of the data of the respective one of the logical chunks, based on the evaluation value of the respective logical chunks.
9 more elements
A storage controller which controls a first storage device and a second storage device included in a tiered storage system, the first storage device comprising a storage area which includes a plurality of physical chunks having a first size, the second storage device comprising a storage area which includes a plurality of physical chunks having the first size, the second storage device having a lower access speed and a larger storage capacity than the first storage device, the storage controller comprising:
- a logical volume management unit which manages a logical volume including a plurality of logical chunks having the first size, the logical volume being provided to a host computer, the storage areas of the first and second storage devices being allocated to the logical volume physical, chunk by physical chunk;
- an access statistics collection controller which collects, during respective monitoring periods, access frequency statistical values representing statuses of accesses to the respective logical chunks;
- an evaluation controller which records a first access frequency statistical value and a second access frequency statistical value associated with a respective one of the logical chunks, the first access frequency statistical value representing a status of access to the respective one of the logical chunks which is in a first location state in which data of the respective one of the logical chunks is located on the first storage device, the second access frequency statistical value representing a status of access to the respective one of the logical chunks which is in a second location state in which data of the respective one of the logical chunks is located on the second storage device, the evaluation controller updating, during the respective monitoring periods, the first or second access frequency statistical value corresponding to a location state of data of the respective one of the logical chunks such that the first access frequency statistical value indicates an access frequency statistical value recorded during a most recent monitoring period in which the data of the respective one of the logical chunks is in the first location state and the second access frequency statistical value indicates an access frequency statistical value recorded during a most recent monitoring period in which the data of the respective one of the logical chunks is in the second location state, based on one of the collected access frequency statistical values, which is associated with the respective one of the logical chunks;
- an evaluation value calculator which calculates an evaluation value based on the first and second access frequency statistical values of the respective one of the logical chunks, the evaluation value indicative of a degree of improvement of access performance obtained when the location state of the data of the respective one of the logical chunks is changed from the second location state to the first location state;
- and
- a relocation controller which determines whether it is necessary to change the location state of the data of the respective one of the logical chunks, based on the evaluation value of the respective logical chunks.
3 more elements
A method, in a storage controller which controls a first storage device and a second storage device, for estimating data location, the first storage device comprising a storage area which includes a plurality of physical chunks having a first size, the second storage device comprising a storage area which includes a plurality of physical chunks having the first size, the second storage device having a lower access speed and a larger storage capacity than the first storage device, the method comprising:
- managing a logical volume including a plurality of logical chunks having the first size, the logical volume being provided to a host computer, the storage areas of the first and second storage devices being allocated to the logical volume physical chunk by physical chunk;
- collecting, during respective monitoring periods, access frequency statistical values representing statuses of access to the respective logical chunks;
- recording a first access frequency statistical value and a second access frequency statistical value associated with a respective one of the logical chunks, the first access frequency statistical value representing a status of access to the respective one of the logical chunks which is in a first location state in which data of the respective one of the logical chunks is located on the first storage device, the second access frequency statistical value representing a status of access to the respective one of the logical chunks which is in a second location state in which data of the respective one of the logical chunks is located on the second storage device;
- updating, during the respective monitoring periods, the first or second access frequency statistical value corresponding to a location state of data of the respective one of the logical chunks such that the first access frequency statistical value indicates an access frequency statistical value recorded during a most recent monitoring period in which the data of the respective one of the logical chunks is in the first location state and the second access frequency statistical value indicates an access frequency statistical value recorded during a most recent monitoring period in which the data of the respective one of the logical chunks is in the second location state, based on one of the collected access frequency statistical values, which is associated with the respective one of the logical chunks;
- calculating an evaluation value based on the first and second access frequency statistical values of the respective one of the logical chunks, the evaluation value indicative of a degree of improvement of access performance obtained when the location state of the data of the respective one of the logical chunks is changed from the second location state to the first location state;
- and
- determining whether it is necessary to change the location state of the data of the respective one of the logical chunks, based on the evaluation value of the respective logical chunks.
4 more elements
Dependencies are inferred from the claim text.