Storage virtualization and storage management to provide higher level storage services

• US 7,415,506 B2
• Filed: 02/13/2002
• Issued: 08/19/2008
• Est. Priority Date: 02/13/2001
• Status: Expired due to Term

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Meyer, Richard, Patel, Dipam, Gajjar, Kumar, Prasad, Chandra, Collins, Jim
• Primary Examiner(s): Cardone; Jason
• Assistant Examiner(s): Gillis; Brian J
• Application Number:
  US10/076,855
• Publication Number:
  US 20020156987A1
• Time in Patent Office: 2,379 Days
• Field of Search: 709/219, 709/212, 709/215, 710/9, 711/112, 711/202, 711/114
• US Class Current: 709/215
• CPC Class Codes: G06F 11/0724 in a multiprocessor or a multi-core unit multiprocessors per se G06F15/80
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: G06F 11/0766 Error or fault reporting or storing
• CPC Class Codes: G06F 11/0793 Remedial or corrective actions recovery from an exception in an instruction pipeline G06F9/3861; by retry G06F11/1402; for recovering from a failure of a protocol instance or entity H04L69/40
• CPC Class Codes: G06F 11/1482 by means of middleware or OS functionality
• CPC Class Codes: G06F 11/201 between storage system components
• CPC Class Codes: G06F 11/2025 using centralised failover control functionality
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality
• CPC Class Codes: G06F 11/2092 Techniques of failing over between control units
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: G06F 12/1458 by checking the subject access rights
• CPC Class Codes: G06F 2201/815 Virtual middleware or OS functionality using virtual machines to implement generic software techniques for error detection or fault masking G06F11/1484
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• 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 3/0614 Improving the reliability of storage systems
• CPC Class Codes: G06F 3/0629 Configuration or reconfiguration of storage systems
• CPC Class Codes: G06F 3/0632 by initialisation or re-initialisation of storage systems
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/067 : Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: H04L 49/357 : Fibre channel switches
• CPC Class Codes: H04L 67/1097 : for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

In a storage server on a storage area network, a media unit manager manages disk space in a manner transparent to the host computers. The media unit manager uses media units corresponding to the physical storage devices on the storage area network to build higher-level media units. The higher level media units can have the attributes of being sliced, concatenated, mirrored, striped, etc. Thus, the host computers need not be aware of the specific physical storage devices themselves, reducing the management and reconfiguration burden on the host computers when storage devices are added to or removed from the storage area network.

Claims

1. A method of operating a storage server that connects a plurality of host computers and a plurality of storage devices, said plurality of storage devices having associated therewith a plurality of physical logical unit numbers (PLUNs), said method comprising:

mapping said plurality of PLUNs to a plurality of first media units;

creating a second media unit from at least a portion of one or more of said plurality of first media units to facilitate abstract block-storage addressing of storage associated with the plurality of PLUNs;

mapping the second media unit to a virtual logical unit number (VLUN) which a host can reference to access data stored in one or more of the storage devices, wherein the plurality of PLUNs are a first storage virtualization level in a storage virtualization hierarchy, the VLUN is a second storage virtualization level in the storage virtualization hierarchy, the plurality of first media units are a third storage virtualization level logically between the first storage virtualization layer and the second storage virtualization layer in the storage virtualization hierarchy, and the second media unit is a fourth storage virtualization level logically between the second storage virtualization layer and the third storage virtualization layer in the storage virtualization hierarchy; and

creating storage constructs between the plurality of first media units and the second media unit using the abstract block-storage addressing as a source of blocks that fulfill requirements from the plurality of host computers for predetermined storage attributes and properties at the second storage virtualization level having persistent information stored on the second media unit to describe and store predetermined storage attributes and properties associated with the storage at the second storage virtualization level.

2. The method of claim 1, fUrther comprising:

using said second media unit when transferring data between said plurality of host computers and said plurality of storage devices.

3. The method of claim 1, wherein said plurality of PLUNs are directly mapped to said plurality of first media units.

4. The method of claim 1, wherein said plurality of PLUNs are indirectly mapped to said plurality of first media units.

5. The method of claim 1, wherein said second media unit is at least one of a slice media unit a concatenation media unit, a striped media unit, or a mirrored media unit.

6. The method of claim 1, wherein said plurality of first media units comprises a plurality of physical media units.

7. The method of claim 1, wherein said plurality of first media units includes at least one of a physical media unit, a slice media unit, a concatenation media unit, a striped media unit, or a mirrored media unit.

8. The method of claim 1, wherein said second media unit is an asynchronous mirrored media unit.

9. The method of claim 1, ftwther comprising:

creating a third media unit from at least a portion of another one or more of said plurality of first media units; and

creating a fourth media unit from said second media unit and said third media unit.

10. The method of claim 9, wherein said second media unit is a first slice media unit, said third media unit is a second slice media unit, and said fourth media unit is a concatenation media unit.

11. The method of claim 9, wherein said second media unit is a first mirrored media unit, said third media unit is a second mirrored media unit, and said fourth media unit is a slice media unit.

12. The method of claim 9, wherein said second media unit is a first slice media unit, said third media unit is a second slice media unit, and said fourth media unit is a mirrored media unit.

13. The method of claim 9, wherein said second media unit is a first synchronous mirrored media unit, said third media unit is a second synchronous mirrored media unit, and said fourth media unit is an asynchronous mirrored media unit.

14. The method of claim 1, wherein said portion of said one or more of said plurality of first media units is a second portion of one of said plurality of first media units, and said second media unit is a slice media unit.

15. The method of claim 1, wherein said portion of said one or more of said plurality of first media units is all of two or more of said plurality of first media units, and said second media unit is a mirrored media unit.

16. The method of claim 1, wherein said plurality of first media units is two or more first media units, wherein said second media unit is a mirrored media unit, and wherein said method further comprises:

disassociating one of said two or more first media units from said mirrored media unit; and

creating a third media unit from the disassociated first media unit, wherein said third media unit comprises a snapshot of said mirrored media unit.

17. The method of claim 16, wherein said method further comprises:

re-associating the disassociated first media unit with said mirrored media unit, after said third media unit is created.

18. The method of claim 1, wherein said method further comprises:

adding a third media unit associated with another of said plurality of PLUNs;

associating said third media unit with said second media unit, wherein said second media unit is a mirrored media unit; and

reconstructing data of said second media unit on said another of said plurality of PLUNs via said third media unit.

19. The method of claim 18, wherein said third media unit is associated with said second media unit to provide a greater level of redundancy.

20. The method of claim 18, wherein said third media unit is associated with said second media unit to replace a failed media unit.

21. The method of claim 1, wherein said portion of one or more of said plurality of first media units comprises a first media unit associated with a first PLUN of said plurality of PLUNs, and wherein said method flirther comprises:

adding a third media unit associated with at least a portion of a second PLUN of said plurality of PLUNs;

associating said third media unit with said second media unit, wherein said second media unit is a mirrored media unit;

reconstructing data of said second media unit on said second PLUN via said third media unit; and

disassociating said third media unit from said second media unit.

22. The method of claim 1, wherein said second media unit is asynchronous mirrored media unit, and wherein said method further comprises:

creating a third media unit from said second media unit and another of said plurality of first media units, wherein said third media unit is an asynchronous mirrored media unit.

23. The method of claim 1, wherein said method is performed in a distributed manner by a plurality of processors.

24. The method of claim 1, wherein said method further comprises:

exporting a first designated media unit of said plurality of first media units to a first virtual LUN;

reconstructing a second designated media unit of said plurality of first media units using said second media unit, wherein said second media unit is a mirrored snapshot media unit;

exporting said second media unit to a second virtual LUN; and

associating a third media unit with said first designated media unit, said first virtual LUN and said second media unit.

25. The method of claim 24, wherein said method further comprises:

creating a fourth media unit from at least a portion of one or more of said plurality of first media units, wherein said fourth media unit is a second mirrored snapshot media unit;

associating said third media unit with said first designated media unit, said first virtual LUN, said second media unit and said fourth media unit;

reconstructing a third designated media unit of said plurality of first media units using said fourth media unit; and

exporting said fourth media unit to a third virtual LUN.

26. The method of claim 24, further comprising, after completion of reconstructing said second designated media unit:

exporting said first designated media unit directly to said first virtual LUN; and

exporting said second designated media unit directly to said second virtual LUN.

27. The method of claim 1, wherein said method further comprises:

exporting a first designated media unit of said plurality of first media units to a first virtual LUN;

creating a second designated media unit of said plurality of first media units, wherein said second designated media unit is smaller than said first designated media unit;

associating said second media unit with said first designated media unit and said second designated media unit, wherein said second media unit is a snapshot media unit;

exporting said second media unit to a second virtual LUN;

creating a third media unit and exporting said third media unit to said first virtual LUN, wherein said third media unit is associated with said first designated media unit and said second media unit; and

creating a fourth media unit and exporting said fourth media unit to a third virtual LUN, wherein said fourth media unit is a second snapshot media unit, and wherein said fourth media unit is associated with said second media unit and a third designated media unit of said plurality of first media units.

28. The method of claim 1, wherein said second media unit is one of a plurality of slice media units associated with one of said plurality of first media units, wherein said method further comprises:

deleting a first virtual LUN associated with a third media unit of said plurality of slice media units, and in response thereto deleting said third media unit; and

deleting a second virtual LUN associated with said second media unit, and in response thereto deleting said second media unit.

29. A storage server comprising:

a physical logical unit number (PLUN) manager to manage data and command transfer to a plurality of storage devices, the plurality of storage devices having a plurality of PLUNs associated therewith;

a virtual logical unit number (VLUN) manager to manage data and command transfer to a plurality of hosts, including to export a plurality of VLUNs to the plurality of hosts such that the hosts can reference the VLUNs to access data stored in the plurality of storage devices; and

a media unit manager to map the PLUNs to the VLUNs by creating a storage virtualization hierarchy including a plurality of levels of virtual media units, wherein the PLUNs are a first storage virtualization level in the storage virtualization hierarchy and the VLUNs are a second storage virtualization level in the storage virtualization hierarchy, the media unit manager to map the plurality of PLUNs to a plurality of first media units and to create a second media unit from at least a portion of one or more of the plurality of first media units making abstract block-storage addressing of storage associated with the plurality of PLUNs available, the second media unit being mapped to a VLUN to export the second media unit to a host, wherein the plurality of first media units are a third storage virtualization level logically between the first storage virtualization level and the second storage virtualization level in the storage virtualization hierarchy and the second media unit is a fourth storage virtualization level logically between the second storage virtualization level and the third storage virtualization level in said storage virtualization hierarchy and creating storage constructs between the plurality of first media units and the second media unit using the abstract block-storage addressing as a source of blocks that fulfill requirements from the plurality of hosts for predetermined storage attributes and properties at the second storage virtualization level having persistent information stored on the second media unit to describe and store predetermined storage attributes and properties associated with the storage at the second storage virtualization level.

30. The storage server of claim 29, wherein said plurality of PLUNs are directly mapped to said plurality of first media units.

31. The storage server of claim 29, wherein said plurality of PLUNs are indirectly mapped to said plurality of first media units.

32. The storage server of claim 29, wherein said second media unit is at least one of a slice media unit, a concatenation media unit, a striped media unit or a mirrored media unit.

33. The storage server of claim 32, wherein said plurality of first media units includes at least one of a physical media unit, a slice media unit, a concatenation media unit a striped media unit, or a mirrored media unit.

34. The storage server of claim 29, wherein said second media unit is an asynchronous mirrored media unit.

35. The storage server of claim 29, wherein the media unit manager further is to:

create a third media unit from at least a portion of another one or more of said plurality of first media units; and

create a fourth media unit from said second media unit and said third media unit.

36. A storage server comprising:

a first interface through which to communicate with a plurality of external host computers;

a second interface through which to communicate with a plurality of external storage devices, said plurality of external storage devices having associated therewith a plurality of physical logical unit numbers (PLUNs);

a processor set comprising at least one processor; and

computer program code executable by the processor set to cause the storage server to execute steps comprising;

mapping said plurality ot PLUNS to a plurality ot tirst media units;

creating a second media unit from at least a portion of one or more of said plurality of first media units to facilitate abstract block-storage addressing of storage associated with the plurality of PLUNs; and

exporting the second media unit to a host by mapping the second media unit to a virtual logical unit number (VLUN) which said host can reference to access data stored in one or more of the plurality of external storage devices, wherein the plurality of PLUNs are a first storage virtualization level in a storage virtualization hierarchy, the VLUN is a second storage virtualization level in the storage virtualization hierarchy, the plurality of first media units are a third storage virtualization level logically between the plurality of PLUNs and the VLUN first storage virtualization level and the second storage virtualization level in the storage virtualization hierarchy, and the second media unit is a fourth storage virtualization level logically between the second storage virtualization level and the third storage virtualization level in the storage virtualization hierarchy; and

creating storage constructs between the plurality of first media units and the second media unit using the abstract block-storage addressing as a source of blocks that fulfill requirements from the plurality of external host computers for predetermined storage attributes and properties at the second storage virtualization level having persistent information stored on the second media unit to describe and store predetermined storage attributes and properties associated with the storage at the second storage virtualization level.

37. The storage server of claim 36, wherein said second media unit is formed from each of said plurality of first media units in their entireties.

38. The storage server of claim 36, wherein said second media unit is formed from only a portion of each of said plurality of first media units.

39. The storage server of claim 36, wherein said second media unit is a mirrored media unit.

40. The storage server of claim 36, further comprising computer program code executable by the processor set to cause the storage server to execute steps comprising:

creating a third media unit from at least a portion of another one or more of said plurality of first media units; and

creating a fourth media unit from said second media unit and said third media unit.

41. A method of operating a storage system, the method comprising:

maintaining a plurality of physical logical unit numbers (PLUNs) that are mapped to a set of one or more physical storage devices;

maintaining a virtual logical unit number (VLUN) that is exportable to an external host;

maintaining a storage virtualization hierarchy that includes the plurality of PLUNs as a first storage virtualization level in the storage virtualization hierarchy, the VLUN at as a second storage virtualization level in the storage virtualization hierarchy, and a plurality of additional storage virtualization levels defined logically between the first storage virtual ization level and the second storage virtualization level in the storage virtualization hierarchy, each of the plurality of additional storage virtualization levels including at least one media unit to facilitate abstract block-storage addressing of storage associated with the plurality of PLUNs; and

creating storage constructs between a plurality of first media units and a second media unit using the abstract block-storage addressing as a source of blocks that fulfill requirements from a plurality of hosts for predetermined storage attributes and properties at the second storage virtualization level having persistent information stored on the second media unit to describe and store predetermined storage attributes and properties associated with the storage at the second storage virtualization level.