Online label maintenance

• US 7,739,447 B1
• Filed: 04/22/2005
• Issued: 06/15/2010
• Est. Priority Date: 04/22/2005
• Status: Active Grant

• Current Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Rodrigues, Steven
• Primary Examiner(s): Bragdon; Reginald G
• Assistant Examiner(s): Ruiz; Aracelis
• Application Number:
  US11/112,622
• Time in Patent Office: 1,880 Days
• Field of Search: 711/114, 711/163, 714/8
• US Class Current: 711/114
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 2211/104 Metadata, i.e. metadata associated with RAID systems with parity

Abstract

One or more parts of a storage system may be serviced while the storage system is online. A storage device may be unincorporated from the storage system while maintaining the storage system active. Access to the storage system may continue unaffected, except for the unincorporated section of the storage system, for example, the storage device and possibly other storage devices. Service may be performed on the unincorporated section of the storage system, and the unincorporated section be incorporated back into the storage system.

Claims

1. A method comprising:

determining that a storage device of a multi-device storage system is unusable within a logical group of storage devices due to an error with label data of the storage device that indicates an association of the storage device with the logical group to which it belongs, the error with the label data causing the storage device to have incorrect information about the association with the logical group, the storage system having multiple logical data containers defining logical groups of storage devices, each data container having software objects to represent the storage devices, where a property of a software object corresponds to a status of the represented storage device;

logically isolating the storage device from the storage system, including isolating the storage device from the logical group to which the storage device belongs, while maintaining storage service access to another storage device in the storage system including maintaining the logical group online, the logically isolating including preventing the storage device from being assimilated into the storage system as a storage resource of a logical group;

performing maintenance on the isolated storage device including modifying the label data on the storage device to indicate a correct association of the storage device with the logical group; and

assimilating the storage device back into the storage system after performing the maintenance.

2. A method according to claim 1, wherein the storage device comprises a magnetic hard disk drive.

3. A method according to claim 1, wherein logically isolating the storage device comprises placing the storage device in a virtual maintenance state.

4. A method according to claim 3, wherein placing the storage device in the virtual maintenance state comprises changing a state of a software object representing the storage device to a state not recognized by the storage system.

5. A method according to claim 1, wherein logically isolating the storage device comprises fracturing a data structure containing a software object representing the storage device, the data structure representing the logical data container defining the logical group to which the storage device belongs.

6. A method according to claim 5, wherein fracturing the data structure containing the storage device comprises temporarily disassociating one or more software objects representing storage devices associated with the data structure.

7. A method according to claim 1, wherein modifying the label data further comprises issuing a maintenance command to determine a correct state of the label data.

8. A method according to claim 7, wherein issuing the maintenance command further comprises:

issuing a command that performs an operation on the storage device and an additional storage device determined to be part of the same logical data structure;

temporarily assimilating the storage device and the additional storage device to perform the operation; and

removing the effects of the temporary assimilation upon completion of the operation.

9. A method according to claim 1, wherein logically isolating the storage device comprises un-assimilating the storage device from the storage system.

10. A method according to claim 9, wherein un-assimilating the storage device from the storage system further comprises:

determining if the storage device is contained within a logical data structure that includes other storage devices; and

if the storage device is contained within a logical data structure, fracturing the logical data structure, and un-assimilating the storage device and the other storage devices associated with the logical data structure.

11. A method according to claim 9, further comprising:

determining if the storage device is contained within a logical data structure that includes a root data structure for the storage system; and

un-assimilating the storage device if the root data structure is not included in the logical data structure of the storage device.

12. A method comprising:

assimilating storage units automatically and dynamically into an operational storage server system, the storage system having multiple logical data containers defining logical groups of storage units, each data container having software objects to represent the storage units, where a property of a software object corresponds to a status of the represented storage unit;

determining label metadata of a storage unit has an error, the label metadata defining a logical data structure associated with the storage unit to indicate a logical group to which the storage unit belongs, where the error with the label metadata causes the storage unit to have incorrect information about the association with the logical data structure, and prevents the storage unit from servicing data requests in the logical group;

marking the storage unit to isolate the storage unit from the logical group, and prevent dynamic assimilation of the storage unit into the operational storage server system; and

while the storage server system, including the associated logical data structure and its associated storage units except for the isolated storage unit, is operational, editing label metadata on the storage unit defining the logical data structure associated with the storage unit.

13. A method according to claim 12, wherein marking the storage unit comprises flagging the storage unit in a memory accessible to the storage server system.

14. A method according to claim 12, wherein marking the storage unit comprises setting a state of the storage unit to a state unknown to the storage server system.

15. A method according to claim 12, wherein marking the storage unit further comprises determining that metadata on the storage unit defining a logical data structure to which the storage unit belongs is corrupted.

16. A method according to claim 12, further comprising restoring the storage unit to permit dynamic assimilation of the storage unit into the storage server system.

17. A method according to claim 16, wherein restoring the storage unit to permit dynamic assimilation comprises changing a state of the storage unit from a maintenance state to an operational state.

18. An article of manufacture comprising a machine accessible recordable/non-recordable medium having content stored thereon to provide instructions to result in an electronic system performing operations including:

logically mapping detected physical storage resources including a storage device, to provide a network storage system, the network storage system having multiple logical data containers defining logical groups of storage devices, where mapping associates storage resources including the storage device to logical groups of storage devices, the logical data containers having software objects to represent associated storage devices;

determining that the storage device has incorrect logical mapping data, which incorrect logical mapping data causes the storage device to having incorrect information about the logical mapping with a logical group to which the storage device belongs;

placing the storage device in a virtual maintenance mode to isolate the storage device from the logical group to which the storage device belongs, including flagging the software object representing the storage device to prevent the storage device from being assimilated into the network storage system;

operating on the storage device in the virtual maintenance mode to correct the logical mapping data; and

incorporating the storage device back into the network storage system into the logical group to which the storage device belongs when the logical mapping data is corrected.

19. An article of manufacture according to claim 18, wherein determining the storage device has incorrect logical mapping data comprises determining that the logical mapping data of the storage device is missing or has incorrect values.

20. An article of manufacture according to claim 18, wherein removing the storage device from the network storage system further comprises:

determining what logical mappings in the network storage system contain the storage device; and

destroying the logical mappings that contain the storage device.

21. An article of manufacture according to claim 18, wherein preventing the storage device from being incorporated into the network storage system comprises maintaining the storage device in a non-incorporable state.

22. An apparatus comprising:

a storage component having code to define operations including isolating an unusable disk of a storage system from data access commands while access is maintained to another disk of the storage system, servicing the isolated disk to restore metadata information on the disk, and incorporating the disk back into the storage system without rebooting the storage system, where the storage system has multiple logical data containers defining logical groups of disks, the logical data containers having software objects to represent disks of the logical groups, and where the isolated disk is part of a logical group of the storage system; and

a processor coupled to the storage component to execute the operations defined in the code;

wherein isolating the unusable disk includes flagging the software object representing the disk to temporarily remove the disk from the logical group to which the disk belongs and prevent the disk from being assimilated into the network storage system; and

wherein incorporating the disk back into the storage system includes removing the flagging of the software object representing the disk and incorporating the disk back into the logical group to which the disk belongs.

23. An apparatus according to claim 22, wherein isolating the unusable disk comprises

modifying a code routine to incorporate the disk back into the storage system to prevent incorporation of the disk as long as it is flagged.

24. An apparatus according to claim 22, wherein the code to define servicing the isolated disk further comprises code to define a temporary incorporation routine to provide a temporary data structure on which a maintenance command may be executed.

25. A storage server comprising:

a processor;

a communications adapter coupled to a network to interface with a client over the network;

a storage adapter coupled to a mass storage subsystem to access one or more mass storage devices of the subsystem on behalf of the client;

a memory coupled to the processor having software, which when executed by the processor, causes the storage server to generate a logical organization of the storage devices through which the storage devices are accessible by the client, the logical organization including data containers having software objects to represent the storage devices and logical groups with which the storage devices are associated, and execute a process to remove one or more of the storage devices from the logical organization to prevent access to the storage device(s) while continuing to allow access to the other storage devices, edit metadata on the removed storage device(s) that identifies a position of the storage device(s) in the logical organization, including flagging the software object(s) representing the removed storage device(s) to temporarily isolate the storage device(s) from the logical group(s) to which they belong and prevent the storage device(s) from being assimilated into the subsystem while the storage device(s) is/are flagged, and allow the client to access the storage device(s) when the metadata is edited.