Patent ID: 8595440
Filing Date: 2013-11-26
Classification: G06F,H04L

Abstract:
1. A file server apparatus that acquires a file from an online storage service connected via a network to provide the file to a user terminal, the file server apparatus comprising: a local cache that stores K divided files among N divided files generated by dividing an original file stored by the online storage service (where K and N are positive integers, and K<N); a mount module that acquires data from the online storage service and the local cache, wherein: the mount module determines whether all divided blocks necessary to provide data corresponding to an I/O request exist in the local cache and acquires the data corresponding to the file I/O request from the divided blocks if the necessary divided blocks exist; the local cache further stores metadata of the original file, the metadata including file update information indicating whether the original file is updated and bit map information indicating a state of the N divided files, and if the I/O request is a write request and at least one of the K divided files stored in the local cache is updated, the mount module sets both the file update information and the bit map information corresponding to the updated divided file to information indicative of the update.