Method and system for maintaining disk location via homeness

• US 7,711,683 B1
• Filed: 11/30/2006
• Issued: 05/04/2010
• Est. Priority Date: 11/30/2006
• Status: Expired due to Fees

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Coatney, Susan M., Watanabe, Steven S., Strange, Stephen H.
• Primary Examiner(s): MIZRAHI, DIANE D
• Application Number:
  US11/606,538
• Time in Patent Office: 1,251 Days
• Field of Search: 707/1, 707/10, 707/103.R, 707/103.X, 707/103.Y, 707/103.Z, 707/100
• US Class Current: 711/100
• 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 16/1827 Management specifically adapted to NAS management of storage area networks [SAN] G06F3/067

Abstract

A method and system manages ownership information about disks in a storage network without the need for an emulated, partner mode system. The method and system provides for ownership information, including a current owner and a home owner for resources, such as disks, to be stored on each disk in a storage system, as well as to be stored in memory on each storage system node in the network. A further aspect of the invention is a disk homeness application program interface (API), which provides commands that can be utilized by an administrator at a host computer to set, modify and display ownership information about each disk in the cluster. Upon a takeover, any node in the network can takeover one or more disks by reading the ownership information stored on the disks or in the tables.

Claims

1. A method for managing ownership of one or more storage devices in a storage network, comprising:

writing ownership information to a predetermined area of each storage device, wherein said information includes;

current owner information, identifying a node that currently serves data access requests directed to a storage device;

home owner information, identifying an originally assigned node that serves data access requests directed to the storage device when the originally assigned node is operational;

performing a takeover of the originally assigned node by a takeover node;

reading the ownership information to determine storage devices to be taken over by the takeover node; and

updating the ownership information stored on each storage device to be taken over to reflect the takeover node as the current owner of the storage devices.

2. The method as defined in claim 1, further comprising:

reading ownership information from a predetermined area of each storage device;

in response to reading the ownership information, creating an ownership table that identifies the one or more storage devices owned by a node reading said ownership information; and

maintaining said ownership table in a node that is the home owner of the storage devices, and at a management station.

3. The method as defined in claim 1, further comprising:

configuring one or more storage devices identified in the ownership table into at least one volume for use by the storage network.

4. The method as defined in claim 1, further comprising:

during sendhome, reassigning the storage devices to a home owner node; and

updating ownership information to indicate that said storage devices are again assigned to the home owner node.

5. The method as defined in claim 1, further comprising:

upon a failure of a node in the storage network, generating a message to one or more nodes in the network instructing the nodes to read ownership information on the storage devices and to take over one or more storage devices based upon the ownership information.

6. The method as defined in claim 5, wherein the step of generating a message further comprises:

instructing one or more nodes to take over one or more storage devices based upon at least one of the current owner information and the home owner information.

7. The method as defined in claim 1, further comprising:

issuing commands at a remote management station to perform at least one of setting, modifying and displaying of ownership information.

8. A computer readable medium containing executable program instructions executed by a processor, comprising:

program instructions that configure application program interface messages for reading, writing and modifying ownership information in an ownership location on a storage device including at least one of current owner information of a node that currently serves data access requests directed to that storage device, and home owner information identifying an originally assigned node that serves data access requests directed to that storage device when the originally assigned node is operational, wherein a takeover node can read the ownership information to determine the storage device belonging to the originally assigned node to perform a takeover for the originally assigned node, and wherein the ownership information stored on the storage device is updated to reflect a takeover node as the current owner of the storage device.

9. The computer readable medium as defined in claim 8, further comprising:

program instructions that send the application program interface messages from a management station or host computer.

10. A storage network, comprising:

one or more storage system nodes each having a least one disk element module, said nodes being configured to be in communication with one another;

a plurality of disks each disk having an ownership and configured to store ownership information including a current owner of the disk and a home owner of the disk, each disk connected to at least one of the disk element modules in the network; and

a processor executing a storage operating system running on each disk element module, the storage operating system having an ownership module that maintains an ownership table configured to store ownership information about one or more disks associated with the network, wherein said ownership module updates the ownership information stored on each disk to reflect a takeover node as the current owner of each disk.

11. The storage network as defined in claim 10 wherein said ownership module further comprises a disk iterator configured to read ownership information from said ownership area on a disk.

12. The storage network as defined in claim 10 wherein said ownership module, upon initial configuration, sets the home owner of each disk to be the current owner.

13. A computer readable medium containing executable program instructions executed by a processor, comprising:

program instructions that write ownership information to a predetermined area of a storage device, wherein said information includes;

current owner information identifying a node that currently serves data access requests directed to that storage device;

home owner information identifying an originally assigned node that serves data access requests directed to the storage device when the originally assigned node is operational

program instructions that perform a takeover of the originally assigned node by a takeover node;

program instructions that read the ownership information to determine storage devices to be taken over by the takeover node; and

program instructions that update the ownership information stored on each storage device to be taken over to reflect the takeover node as the current owner of the storage devices.

14. The computer readable medium as defined in claim 13, further comprising:

program instructions that read ownership information from the predetermined area of each storage device;

in response to reading the ownership information, program instructions that create an ownership table that identifies the storage device owned by a node reading said ownership information; and

program instructions that maintain the ownership table in the node that is the home owner of the storage devices, and a management station.

15. The computer readable medium as defined in claim 13, further comprising:

program instructions that generate a message to one or more nodes in the network instructing the nodes to read ownership information on the storage devices in the network and to take over one or more storage devices based upon the ownership information upon a failure of a node in a storage network.

16. The computer readable medium as defined in claim 13 wherein writing ownership information further comprises program instructions that write ownership information for more than one portion of a disk when portions of said disk are owned by different nodes.

17. A system for using a computer for managing ownership of one or more storage devices in a storage network, the system comprising:

means for writing ownership information to a predetermined area of each storage device, wherein said information includes;

current owner information, identifying a node that currently serves data access requests directed to a storage device;

home owner information, identifying an originally assigned node that serves data access requests directed to the storage device when the originally assigned node is operational;

means for performing a takeover of the originally assigned node by a takeover node, wherein the takeover node comprises a processor executing the means for performing the takeover;

means for reading the ownership information to determine storage devices to be taken over by the takeover node; and

means for updating the ownership information stored on each storage device to be taken over to reflect the takeover node as the current owner of the storage devices.

18. A storage network, comprising:

one or more storage system nodes each having a least one disk element module, said nodes being configured to be in communication with one another;

a plurality of storage devices each storage device having an ownership and configured to store ownership information including a current owner of the storage device and a home owner of the storage device, each storage device connected to at least one of the disk element modules in the network; and

a processor executing a storage operating system running on each disk element module, the storage operating system having an ownership module that maintains an ownership table configured to store ownership information about one or more storage devices associated with the network, wherein said ownership module updates the ownership information stored on each storage device to reflect a takeover node as the current owner of each storage device.