Method and apparatus for providing storage control in a network of storage controllers

• US 7,401,081 B2
• Filed: 05/29/2003
• Issued: 07/15/2008
• Est. Priority Date: 11/28/2002
• Status: Active Grant

• Current Assignee: International Business Machines SA (International Business Machines Corporation)
• Original Assignee: International Business Machines Corporation
• Inventors: Fuente, Carlos Francisco, Scales, William James
• Primary Examiner(s): Alam; Hosain
• Assistant Examiner(s): Lin; Shew-Fen
• Application Number:
  US10/447,351
• Publication Number:
  US 20040107176A1
• Time in Patent Office: 1,874 Days
• Field of Search: 707 1- 10, 707100-104, 707200-206, 711100-120, 709/219
• US Class Current: 711/100
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database
• CPC Class Codes: Y10S 707/99939 Privileged access

Abstract

An apparatus for providing storage control in a network of storage controllers is disclosed. The apparatus includes an owner storage controller; an I/O performing component, an ownership assignment component, a lock manager and a messaging component. The ownership assignment component assigns ownership of metadata for data to an owner storage controller. The lock manager controls the locking of metadata during I/O. The messaging component passes messages among storage controllers to request metadata state, to grant locks, to request release of locks, and to signal lock release. The I/O is performed on data whose metadata is owned by an owner storage controller, subject to compliance with metadata lock protocols controlled by the owner storage controller, and any copy of the data held from time to time is maintained in a coherency relation with the data.

Claims

1. A method for providing control on metadata within a network of storage controllers, said method comprising:

designating one of said storage controllers as an owner storage controller, wherein said owner storage controller owns metadata controlling all input/output (I/O) operations associated with a region of storage;

designating remaining of said storage controllers as client storage controllers;

in response to an I/O request to one of said client storage controllers, suspending said I/O request by said one client storage controller;

determining by said owner storage controller, whether or not said region of storage has already been copied;

in a determination that said region of storage has been copied, unpending said I/O request by said one client storage controller to process said I/O request; and

in a determination that said region of storage has not been copied,

placing a lock record against said metadata associated with said region of storage;

copying data within said region of storage by said owner storage controller; and

releasing said lock record to process said I/O request.

2. The method of claim 1, wherein said copying further includes performing a copy-on-write operation.

3. The method of claim 2, wherein said copying further includes marking in said metadata the region affected as having been copied.

4. The method of claim 1, wherein said copying is performed by using a Flash Copy algorithm.