Storage system and storage cost optimization method

1. A storage system comprising:

a storage device;

a memory; and

a processor configured to control input and output of data to and from the storage device, wherein

the processor monitors a storage amount and a read amount,

the storage amount is at least one of a write amount and a physical use amount,

the write amount is a total amount of data received as a write target, and

the physical use amount is a total amount of data physically stored in the storage device, and

the processor calculates a fee as a storage cost that is a cost related to use of the storage device in a target period, based on a storage amount and a read amount in the target period in accordance with a result of the monitoring.

2. The storage system according to claim 1 , wherein

the processor further determines a fee in the target period based on a read amount in a period before the target period.

3. The storage system according to claim 1 , wherein

the processor performs a data amount reduction processing, which is at least one of compression and deduplication, to reduce an amount of data stored in the storage device, and

the processor increases a data amount reduction rate of the data stored in the storage device according to an elapsed time from a write time point of the data.

4. The storage system according to claim 1 , wherein

the processor performs a data amount reduction processing, which is at least one of compression and deduplication, to reduce an amount of data stored in the storage device, and

the processor calculates a fee in the target period based on a logical storage cost determined for the target period, and

the logical storage cost is a fee per unit amount of the write amount, and is a fee determined based on the physical use amount and a physical storage cost that is a fee per unit amount of the physical use amount.

5. The storage system according to claim 4 , wherein

the logical storage cost is a fee determined based on the read amount and a read cost that is a fee per unit amount of the read amount.

6. The storage system according to claim 5 , wherein

the processor

predicts a physical use amount of a future period that is a certain period after the target period, based on a time-series physical use amount before the target period,

predicts a read amount of the future period, based on a time-series read amount before the target period, and

determines the logical storage cost of the future period, based on the predicted physical use amount, the physical storage cost, the predicted read amount, and the read cost.

7. The storage system according to claim 5 , wherein

the processor

predicts a physical use amount of a future period that is a certain period after the target period, based on a time-series physical use amount before the target period, and

determines the logical storage cost of the future period, based on the predicted physical use amount and the physical storage cost.

8. The storage system according to claim 1 , wherein

a physical storage cost, which is a fee per unit amount of the physical use amount, is common to a plurality of users of the storage device, and

the processor calculates, for each user, a fee in the target period for the user based on a data amount reduction rate of data taken as a write target for the user.

9. The storage system according to claim 1 , wherein

the processor receives one or more cost conditions designated by a user as cost conditions that are conditions related to a fee in the target period, and

the processor performs a data amount reduction processing for maintaining that the one or more cost conditions are satisfied.

10. The storage system according to claim 9 , wherein

the processor receives one or more reduction conditions designated by a user as reduction conditions that are conditions related to the data amount reduction processing, and

the processor determines whether the data amount reduction processing for maintaining that the one or more cost conditions are satisfied satisfies the one or more reduction conditions, and issues an alert if a result of the determination is false.

11. The storage system according to claim 1 , wherein

the processor performs a lossy compression processing to reduce an amount of data stored in the storage device,

the processor monitors a frequency of data, which is taken as a read target, stored in the storage device, and

the processor performs the lossy compression processing on data, which is taken as a read target at a relatively low frequency, among the data stored in the storage device.

12. The storage system according to claim 1 , wherein

the processor performs a data amount reduction processing, which is at least one of compression and deduplication, to reduce an amount of data stored in the storage device, and

the processor controls a data reduction rate of the data in accordance with a read frequency of the data stored in the storage device.

13. The storage system according to claim 12 , wherein

the processor makes a data amount reduction rate of data taken as a read target at a relatively high frequency lower than a data amount reduction rate of data taken as a read target at a relatively low frequency.

14. A cost optimization method, comprising:

when write target data is received, storing the data to a storage device and recording a write time point of the data to a memory, and

calculating a fee related to use of the storage device in a target period, based on a data amount related to a write and an elapsed time from a write time point of data taken as a write target to the target period.

15. A computer program for causing a computer to execute a processing, the processing comprising:

when write target data is received, storing the data to a storage device and recording a write time point of the data to a memory, and

calculating a fee related to use of the storage device in a target period, based on a data amount related to a write and an elapsed time from a write time point of data taken as a write target to the target period.