Fujitsu Corporation

Toshihiko Yaguchi

Mamoru Yokoyama

Yoshihisa Chujo

A data access management system in a distributed processing system capable of immediately restoring the system as a whole, has computers connected to each other via LAN, and a secondary storage device to which the computers are connected via data transfer paths. An access control subsystem for executing a data access to the secondary storage device is executed on each of the computers. A file management subsystem for giving an authority for writing the data to each access control subsystem, is executed on specified computer. When the file management subsystem transmits, to a certain access control subsystem, access control information indicating the authority for writing the data to a specified block on the secondary storage device, the same access control information is saved in the transmitted-side access control subsystem, and its record is retained in the file management subsystem. If the file management subsystem falls into a process-down, a standby file management subsystem is determined to become a new file management subsystem. Then this standby file management subsystem requests each of the access control subsystems to notify of the access control information saved by each of the access control subsystems.

Data access management system in distributed processing system

A distributed processing system which enables a plurality of computers to make quick access to a shared storage unit. A storage quota management unit manages storage quotas, which limit the total amount of data that each user can store on the shared storage unit. When a write request to the shared storage unit is issued at a certain computer, a user identification unit identifies the requesting user. Then a free quota calculation unit calculates the remaining free storage quota of the identified user. A reserve space allocation unit allocates an appropriate reserve space to the computer according to the remaining free storage quota, allowing the computer to use the allocated reserve space at its discretion to handle the user's data write request.

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Kawasaki, Japan

Toshihiko Yaguchi