1. A computer system, comprising: a server including a first processor, a first memory, a cache device in which a server cache is set, and a first interface, where the first memory stores instructions that, when executed by the processor, causes the processor to: execute an operating system for controlling the server, the operating system including a cache driver for controlling the server cache, execute an application providing a service, and store data used by the application in the server cache, a storage system including a second processor, a second memory, and a second interface coupled to the first interface, and a plurality of storage devices for storing data used by the application, where the second memory includes a storage cache for temporarily storing data to be written to the storage devices, and instructions that, when executed by the second processor, cause the second processor to: control the storage system, wherein the operating system is configured to hold access information storing a frequency of reading data from a plurality of areas of the storage devices and a frequency of writing data to the plurality of areas of the storage devices, and wherein the cache driver is configured to: update the access information when an I/O request is received from the application; analyze access characteristics of a target area of the I/O request based on the updated access information; determine whether to store data of the I/O request in the server cache based on the frequency of reading data from the target area and frequency of writing data to the target area; when the target area is frequently written, storing the data of the I/O request in the storage cache; when the target area is frequently read, storing the data of the I/O request in the server cache; and wherein, when the I/O request is a read request to read first data in the target area, the cache driver is configured to: determine whether the first data is stored in the server cache; when the first data is not stored in the server cache, transmit the read request to the storage system; update the frequency of reading the target area in the access information; determine whether the target area is frequently read by the application based on the updated access information; and when the target area is frequently read by the application, store the first data into the server cache, and wherein, when the I/O request is a write request to write second data in the target area, the cache driver is configured to: determine whether the data of the target area is stored in the server cache; when the data of the target area is stored in the server cache, update the data of the target area in the server cache with the second data; transmit the write request to the storage system; update the frequency of writing the target area in the access information; determine whether the target area is frequently written by the application based on the updated access information; and when the target area is frequently written by the application, invalidate the second data stored in the server cache.