Cloud Storage Arrangement and Method of Operating Thereof

• US 20130332700A1
• Filed: 02/22/2012
• Published: 12/12/2013
• Est. Priority Date: 02/22/2011
• Status: Active Grant

• Current Assignee: Infinidat Ltd.
• Original Assignee: Infinidat Ltd.
• Inventors: Kopylovitz, Haim, Corry, Leo, Yochai, Yechiel
• Granted Patent: US 9,645,943 B2
• Time in Patent Office: Days
• US Class Current: 711/209
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• 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]

Abstract

There is provided a storage arrangement and a method of operating thereof. The storage arrangement comprises a first storage system and one or more second storage systems operatively coupled to the first storage system. First control layer is operable to handle a first logical address space comprising a first logical group characterized by a plurality of logical block addresses; first control layer comprises a first mapping module handling a first mapping structure associated with first logical group. Each second control layer comprises, respectively, a second mapping module handling a second mapping structure associated with first logical group. The first mapping structure is configured to provide mapping between logical addresses related to first logical group and corresponding addresses related to first physical address spaces, and/or to point to respective second mapping structure configured to provide mapping between these logical addresses and corresponding addresses related to respective second physical address spaces.

Claims

1. A storage arrangement comprising a first storage system comprising a first physical storage space constituted by a first plurality of physical storage devices controlled by one or more first storage control devices constituting a first control layer, and one or more second storage systems operatively coupled to the first storage system and each comprising a second physical storage space constituted by a second plurality of physical storage devices controlled by one or more second storage control devices constituting a second control layer;

wherein the first control layer is operable to handle a first logical address space comprising at least one first logical group characterized by a plurality of logical block addresses;

wherein said first control layer comprises a first mapping module handling a first mapping structure associated with said at least one first logical group;

wherein each said second control layer comprises, respectively, a second mapping module handling a second mapping structure associated with said at least one first logical group; and

wherein the first mapping structure is configured to provide mapping between logical addresses related to said at least one first logical group and corresponding addresses related to the first physical address spaces, and/or to point to respective second mapping structure configured to provide mapping between logical addresses related to said at least one first logical group and corresponding addresses related to respective second physical address spaces.

2. The storage arrangement of claim 1, wherein the logical group is selected from a group comprising one or more logical volumes, one or more virtual partitions, one or more snapshots, one or more combinations of a given logical volume and its respective one or more snapshots.

3. The storage arrangement of claim 1 or 2, wherein the first storage system is designated as a sole storage system physically accommodating data related to said at least one first logical group, and the first mapping structure is designated as a sole mapping structure to be modified resulting in modifications related to said at least one first logical group.

4. The storage arrangement of any one of claims 1-3, wherein the mapping between one or more contiguous ranges of addresses related to said at least one first logical group and one or more contiguous ranges of addresses related to the corresponding physical addresses is provided by a plurality of mapping trees;

wherein each storage system is associated with its own tree assigned to said certain logical group;

wherein the storage control devices of different storage systems are configured to independently handle the mapping trees associated with the respective storage systems; and

wherein the leaves of each mapping tree are associated with values indicating a mapping tree responsible for mapping the range of logical addresses represented by respective leaves into physical addresses handled by respective storage system and/or indicating corresponding addresses related to physical address space of the respective storage system.

5. The storage arrangement of any one of claims 1-4, wherein the first mapping structure comprises at least one ordered tree data structure comprising one or more leaves and wherein a) a depth of a leaf in the tree represents a length of a contiguous range of addresses related to said at least one first logical group;

b) a path followed from a tree root to the leaf indicates an offset of the respective range of addresses within said at least one first given logical group;

c) a value associated with the leaf indicates an offset of respective contiguous range of addresses related to the first physical storage space and corresponding to said contiguous range of addresses related to said at least one first logical group and/or points to a respective second mapping structure handling mapping of said contiguous range of addresses related to said at least one first logical group to addresses related to respective second physical storage space.

6. The storage arrangement of claim 5, wherein the first storage system is designated as a sole storage system physically accommodating data related to said at least one first logical group, and the respective first mapping tree is designated as a sole mapping tree to be modified resulting in modifications related to said at least one first logical group, and

wherein mapping trees associated with all second storage systems and corresponding to said at least one first logical group are handled as degenerated trees, each one with a single leaf associated with respective value indicating said first mapping tree for mapping addresses corresponding to said at least one first logical group.

7. The storage arrangement of any one of claims 1-6, wherein the first control layer further comprises a first virtual layer operable to represent the logical address space, said first virtual layer characterized by a plurality of virtual unit addresses (VUA), and/or further comprises a second virtual layer operable to represent the physical storage space, said second virtual layer characterized by a plurality of virtual disk addresses (VDA), and wherein mapping between contiguous ranges of addresses related to the logical address space and contiguous ranges of addresses related to the physical address space comprises at least one of the mapping options selected from a group comprising:

a) mapping between addresses characterizing the logical address space (LBA) and addresses characterizing the physical address space (DBA);

b) mapping between VUA and VDA addresses;

c) mapping between LBA and VDA addresses; and

d) mapping between VUA and DBA addresses.

8. The storage arrangement of any one of claims 1-7, wherein the first and the second storage systems are part of a cloud storage arrangement.

9. The storage arrangement of any one of claims 1-7, wherein the first and the second storage systems constitute a storage cluster.

10. A method of operating a storage arrangement comprising two or more operatively coupled storage system each comprising a respective physical storage space constituted by a plurality of physical storage devices controlled by one or more storage control devices constituting a respective control layer, the method comprising:

configuring the storage arrangement to handle a logical group characterized by a plurality of logical block addresses;

wherein said configuring comprises configuring in each control layer a mapping structure associated with said logical group, each mapping structure handling mapping between addresses related to said logical group and addresses related to the corresponding physical address space in respective storage system;

responsive to receiving by a storage system an I/O request addressed to at least one contiguous address range comprised in said logical group, identifying among the mapping structures a mapping structure handling mapping said at least one range to corresponding addresses related to physical address space in respective storage system;

mapping said at least one range into corresponding addresses using the identified mapping structure; and

serving the received I/O request.

11. The method of claim 10, wherein the I/O request is a read request, and wherein said read request is served by a storage system that received the request.

12. The method of claim 10 or 11, wherein the I/O request is a write request, and wherein said write request is served by a storage system corresponding to the identified mapping structure.

13. The method of claim 12 further comprising updating the identified mapping structure in accordance with the served write request.

14. The method of any one of claims 10-13, wherein each mapping structure is configured to provide mapping between logical addresses related to said logical group and corresponding addresses related to the physical address space of respective storage system and/or to point to another mapping structure in order to provide mapping between logical addresses related to said logical group and addresses corresponding to the logical group and related to respective another physical address spaces.

15. The method of any one of claims 10-14, wherein the logical group is selected from a group comprising one or more logical volumes, one or more virtual partitions, one or more snapshots, one or more combinations of a given logical volume and its respective one or more snapshots.

16. The method of any one of claims 10-15, wherein one of the storage systems is designated as a sole storage system physically accommodating data related to said logical group, and the respective mapping structure is designated as a sole mapping structure to be modified resulting in modifications related to said logical group.

17. The method of any one of claims 10-16, wherein each mapping structure comprises at least one ordered tree data structure comprising one or more leaves and wherein a) a depth of a leaf in the tree represents a length of a contiguous range of addresses related to said logical group;

b) a path followed from a tree root to the leaf indicates an offset of the respective range of addresses within said logical group;

c) a value associated with the leaf indicates an offset of respective contiguous range of addresses related to physical storage space in respective storage system and corresponding to said contiguous range of addresses related to said logical group and/or points to another mapping structure handling mapping of said contiguous range of addresses related to said logical group to corresponding addresses related to physical storage space in respective another storage system.

18. The method of claim 17 wherein one of the storage system is designated as a sole storage system physically accommodating data related to said logical group, and the respective mapping tree is designated as a sole mapping tree to be modified resulting in modifications related to said logical group, and

wherein mapping trees associated with all other storage systems and corresponding to said logical group are handled as degenerated trees, each one with a single leaf associated with respective value indicating said designated mapping tree for mapping addresses corresponding to said logical group.

19. The method of any one of claims 10 -18, wherein each control layer further comprises a first virtual layer operable to represent the logical address space, said first virtual layer characterized by a plurality of virtual unit addresses (VUA), and/or further comprises a second virtual layer operable to represent the physical storage space, said second virtual layer characterized by a plurality of virtual disk addresses (VDA), and wherein mapping between contiguous ranges of addresses related to the logical address space and contiguous ranges of addresses related to the physical address space comprises at least one of the mapping options selected from a group comprising:

a) mapping between addresses characterizing the logical address space (LBA) and addresses characterizing the physical address space (DBA);

b) mapping between VUA and VDA addresses;

c) mapping between LBA and VDA addresses; and

d) mapping between VUA and DBA addresses.

20. A computer program comprising computer program code means for performing the method of any of claims 10-19 when said program is run on a computer.

21. A computer program as claimed in claim 20 embodied on a computer readable medium.