Cache device, data management method, program, and cache system

A data management method which uses a cache device for temporarily storing data which is transmitted and received between a user terminal and a storage device, the method comprising:

• recording, by a data recorder, at a storing part, cache data and buffer data;
• wherein the cache data comprises data which is to be stored at the storage device, and
• wherein the buffer data comprises data which is to be written to the storage device;
• determining, by a deleted cache determining device, the cache data which is to be deleted from the storing part if a sum of a data amount of the data which is recorded at the storing part and a data amount of the cache data which is stored at the storing part and a data amount of the buffer data which is stored at the storing part is equal to or more than a predetermined threshold;
• deleting, by a cache deleting device, from the storing part, the cache data which is determined by the deleted cache determining device;
• transmitting, by a buffer transmitter, the buffer data which is stored at the storing part to the storage device;
• deleting, by a buffer deleting device, from the storing part, the buffer data which is transmitted by the buffer transmitter;
• and
• determining, by a transmission rate determining device, a transmission rate of the buffer data such that the larger the cross traffic number in a network between the storage device and the cache device, the slower the transmission rate;
• wherein the buffer transmitter transmits the buffer data to the storage device at the transmission rate which is determined by the transmission rate determining device.

A non-transitory computer readable storage medium storing a program for making a cache device which stores temporarily data transmitted and received between a user terminal and a storage device perform operations comprising:

• recording, by a data recorder, at a storing part, cache data, and buffer data;
• wherein the cache data comprises data which is to be stored at the storage device, and
• wherein the buffer data comprises data which is to be written to the storage device;
• determining, by a deleted cache determining device, the cache data which is to be deleted from the storing part if a sum of a data amount of the data which is recorded at the storing part and a data amount of the cache data which is stored at the storing part and a data amount of the buffer data which is stored at the storing part is equal to or more than a predetermined threshold;
• deleting, by a cache deleting device, from the storing part, the cache data which is determined by the deleted cache determining device;
• transmitting, by a buffer transmitter, the buffer data which is stored at the storing part to the storage device;
• deleting, by a buffer deleting device, from the storing part, the buffer data which is transmitted by the buffer transmitter;
• and
• determining, by a transmission rate determining device, a transmission rate of the buffer data such that the larger the cross traffic number in a network between the storage device and the cache device, the slower the transmission rate;
• wherein the buffer transmitter transmits the buffer data to the storage device at the transmission rate which is determined by the transmission rate determining device.

A cache system which comprises a storage device which stores a data, a user terminal which reads data from the storage device and writes data to the storage device, and a cache device which temporarily stores data which is transmitted and received between the user terminal and the storage device;

• wherein the cache device comprises:
• a data recorder which records cache data and buffer data at a storing part;
• wherein the cache data comprises data which is to be stored at the storage device, and
• wherein the buffer data comprises data which is to be written to the storage device;
• a deleted cache determining device which determines the cache data which is to be deleted from the storing part if a sum of a data amount of the data which is recorded at the storing part and a data amount of the cache data which is stored at the storing part and a data amount of the buffer data which is stored at the storing part is equal to or more than a predetermined threshold;
• a cache deleting device which deletes, from the storing part, the cache data which is determined by the deleted cache determining device;
• a buffer transmitter which transmits the buffer data which is stored at the storing part to the storage device;
• a buffer deleting device which deletes, from the storing part, the buffer data which is transmitted by the buffer transmitter;
• and
• a transmission rate determining device which determines a transmission rate of the buffer data such that the larger the cross traffic number in a network between the storage device and the cache device, the slower the transmission rate;
• wherein the buffer transmitter transmits the buffer data to the storage device at the transmission rate which is determined by the transmission rate determining device.