Storage system having volatile memory and non-volatile memory
AssigneeHitachi, Ltd.
InventorsNaoki Inoue, Yasuyuki Nagasoe
Life of this patent
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Abstract
A storage system including: a plurality of storage devices; a volatile memory which temporarily stores data; a nonvolatile memory; a battery saving power; a cache control unit which sets, according to battery charging rate of the battery, a part of the data stored in the volatile memory as save target data which are to be saved to the nonvolatile memory when power interruption occurs, and saves the part of the data, which is set as the save target data, to the nonvolatile memory by using power of the battery when power interruption occurs.
Claims8
A storage system comprising:
- a plurality of storage devices;
- a volatile memory which temporarily stores data;
- a nonvolatile memory;
- a battery saving power;
- and
- a cache control unit which sets, according to battery charging rate of the battery, a part of the data stored in the volatile memory as save target data which are to be saved to the nonvolatile memory when power interruption occurs, and saves the part of the data, which is set as the save target data, to the nonvolatile memory by using power of the battery when power interruption occurs;
- wherein when the micro processor receives write command from the host computer:
- the micro processor determines whether sum of the amount of data corresponding to the write command and an amount of dirty data exceeds a first threshold which is determined by the battery charging rate;
- the microprocessor temporality stores the data corresponding to the write command in the volatile memory as the dirty data if the sum of the amount of data corresponding to the write command and the amount of dirty data does not exceed the first threshold;
- and
- the microprocessor stores the data corresponding to the write command in the volatile memory as clean data, and writes the data corresponding to the write command to the plurality of storage devices if the sum of the amount of data corresponding to the write command and the amount of dirty data exceeds the first threshold.
A storage system method effected by a storage system including:
- a plurality of storage devices;
- a volatile memory which temporarily stores data;
- a nonvolatile memory;
- a battery saving power;
- and
- a cache control unit;
- where the storage system method comprises:
- setting, according to battery charging rate of the battery, a part of the data stored in the volatile memory as save target data which are to be saved to the nonvolatile memory when power interruption occurs, and saving the part of the data, which is set as the save target data, to the nonvolatile memory by using power of the battery when power interruption occurs;
- the storage system method further comprising:
- wherein when the micro processor receives write command from the host computer, the micro processor:
- determines whether sum of the amount of data corresponding to the write command and an amount of dirty data exceeds a first threshold which is determined by the battery charging rate;
- temporality stores the data corresponding to the write command in the volatile memory as the dirty data if the sum of the amount of data corresponding to the write command and the amount of dirty data does not exceed the first threshold;
- and
- stores the data corresponding to the write command in the volatile memory as clean data, and writes the data corresponding to the write command to the plurality of storage devices if the sum of the amount of data corresponding to the write command and the amount of dirty data exceeds the first threshold.
Dependencies are inferred from the claim text.