Patent ID: 7529892
Filing Date: 2009-05-05
Classification: G06F

Abstract:
1. A file server, comprising: a control unit; a cache memory for temporarily storing data accessed by a client computer; an interface coupled to the client computer; and an interface coupled to a disk device, wherein a plurality of files is stored in the disk device, wherein a first file of the plurality of files contains metadata, which contains information that identifies the first file, wherein the control unit incorporates, into the metadata, related file information, wherein the related file information comprises: wherein when the first file is accessed by the client computer, the control unit refers to the related file information to obtain the second file, the access type, the location of the block, the frequency information, and the access count, wherein when the frequency information indicates that the frequency is within a first range, the control unit performs readahead processing by reading, from the obtained second file stored in the disk device, data in the obtained location of the block and corresponding to the obtained access type, and the control unit stores the read data in the cache memory, wherein when the frequency information indicates that the frequency is within a second ranae and the access count exceeds a predetermined value, the control unit performs readahead processing by reading, from the obtained second file stored in the disk device. data in the obtained location of the block, and corresponding to the obtained access type, and the control unit stores the read data in the cache memory, wherein when the frequency information indicates that the frequency is within a third range, the control unit does not perform readahead processing of the second file, wherein the first range, the second ranae and the third range are exclusive of each other, wherein the access type is information representing one of an append write and a partial write, wherein, when the obtained access type represents the append write, the control unit reads data containing a tail end of the second file stored in the disk device to store the read data in the cache memory, and wherein, when the obtained access type represents the partial write, the control unit reads a data block containing a partial write point of the second file stored in the disk device to store the read data in the cache memory.