Distributed processing system

• US 20020023156A1
• Filed: 03/23/2001
• Published: 02/21/2002
• Est. Priority Date: 08/16/2000
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Yaguchi, Toshihiko, Chujo, Yoshihisa
• Granted Patent: US 7,017,016 B2
• Time in Patent Office: Days
• US Class Current: 709/226
• CPC Class Codes: G06F 16/122 using management policies backup systems G06F11/1446; file migration policies for HSM systems G06F16/185
• CPC Class Codes: G06F 16/1727 Details of free space management performed by the file system saving storage space on storage systems G06F3/0608; management of blocks in storage devices G06F3/064

Abstract

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.

Claims

1. A distributed processing system which has a shared storage unit shared by a plurality of computers, the system comprising:

storage quota management means for managing a storage quota of each user, the storage quota limiting the total amount of data that each user is allowed to store on the shared storage unit;

user identification means for identifying a particular user who has issued a write request in an attempt to store data into the shared storage unit;

free quota calculation means for calculating free storage quota of the particular user identified by said user identification means; and

reserve space allocation means for allocating a reserve space to a requesting computer according to the free storage quota calculated by said free quota calculation means, the reserve space being an amount of storage space on the shared storage unit which is to be managed at the discretion of the requesting computer.

2. The distributed processing system according to claim 1, wherein:

said reserve space allocation means allocates the reserve space as a predetermined amount of space out of the free storage quota, when the free storage quota exceeds a predetermined threshold; and

said reserve space allocation means allocates the reserve space as a fraction (1/N) of the free storage quota to the requesting computer, when the free storage quota falls below the predetermined threshold, where N is the number of computers in the system.

3. The distributed processing system according to claim 2, wherein said reserve space allocation means allocates a null reserve space, when the free storage quota falls below another predetermined threshold.

4. The distributed processing system according to claim 1, wherein:

said storage quota management means further manages a storage quota for each group of users; and

said free quota calculation means calculates the free storage quota of the group to which the identified user belong.

5. The distributed processing system according to claim 1, wherein:

said storage quota management means is deactivated initially; and

when said storage quota management means is brought into an active state, each of the computers reports to said storage quota management means the amount of storage space in the shared storage unit that is not reported yet but currently used by each user.

6. A distributed processing method which controls access to a shared storage unit shared by a plurality of computers, the system comprising:

(a) managing a storage quota of each user, the storage quota limiting the total amount of data that each user is allowed to store on the shared storage unit;

(b) identifying a particular user who has issued a write request in an attempt to store data into the shared storage unit;

(c) calculating free storage quota of the particular user identified by said user identification means; and

(d) allocating a reserve space to a requesting computer according to the free quota calculated by said free quota calculation means, the reserve space being an amount of storage space on the shared storage unit which is to be managed at the discretion of the requesting computer.