System and method for dynamic LUN mapping

• US 20050235132A1
• Filed: 06/20/2005
• Published: 10/20/2005
• Est. Priority Date: 11/26/2003
• Status: Abandoned Application

• Current Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Original Assignee: Veritas Operating Corporation (Gen Digital Inc.)
• Inventors: Aglaia Kong, Chio Fai, Karr, Ronald S.
• Application Number:
  US11/156,821
• Publication Number:
  US 20050235132A1
• Time in Patent Office: Days
• US Class Current: 711/203
• 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 3/0664 at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A system for dynamic logical unit (LUN) mapping includes a host and an off-host virtualizer. The off-host virtualizer may be configured to present a virtual storage device that includes one or more regions that are initially unmapped to virtual storage, and to make the virtual storage device accessible to the host. The host may include a storage software stack including a first layer configured to detect and access the virtual storage device as if the virtual storage device were mapped to physical storage. Subsequently, the off-host virtualizer may be configured to dynamically map physical storage and/or logical volumes to the virtual storage device.

Claims

1. A system comprising:

a first host; and

an off-host virtualizer;

wherein the off-host virtualizer is configured to;

present a first virtual storage device comprising one or more regions that are not initially mapped to physical storage; and

make the first virtual storage device accessible to the first host;

wherein the first host comprises a storage software stack including a first layer;

wherein the first layer is configured to detect and access the first virtual storage device as if the first virtual storage device were mapped to physical storage.

2. The system as recited in claim 1, wherein a portion of first virtual storage device is mapped to metadata formatted according to a requirement of an operating system in use at the first host.

3. The system as recited in claim 2, wherein the metadata comprises a partition table including entries corresponding to one or more partitions, wherein at least one partition of the one or more partitions maps the one or more regions that are not initially mapped to physical storage.

4. The system as recited in claim 2, wherein the metadata comprises one or more metadata entries including a first metadata entry, wherein the off-host virtualizer is further configured to:

generate contents of the first metadata entry and position the first metadata entry at a particular offset within the virtual storage device, wherein the contents and the particular offset are indicative of a successful initialization of the first virtual storage device according to the operating system.

5. The system as recited in claim 1, further comprising an additional storage device, wherein the software storage stack comprises a second layer, wherein the off-host virtualizer is further configured to:

dynamically map a first region of the additional storage device to a particular region of the first virtual storage device; and

wherein the second layer is configured to access the first region of the additional storage device via the first layer.

6. The system as recited in claim 1, wherein the off-host virtualizer includes at least one of:

a virtualization appliance and a virtualizing switch.

7. The system as recited in claim 1, further comprising two or more physical storage devices including a first physical storage device and a second physical storage device, wherein the off-host virtualizer is further configured to:

dynamically map a first range of storage within the first physical storage device and a second range of storage within the second physical storage device to a respective address range within the first virtual storage device.

8. The system as recited in recited in claim 1, further comprising a physical storage device and a second host, wherein the off-host virtualizer is further configured to:

present a second virtual storage device comprising one or more regions that are not initially mapped to physical storage; and

make the second virtual storage device accessible to the second host;

wherein the second host comprises a second storage software stack including a first layer;

wherein the first layer of the second storage software stack is configured to detect and access the second virtual storage device as if the second virtual storage device were mapped to physical storage;

wherein the off-host virtualizer is further configured to;

dynamically map a first physical address range of the physical storage device to a first virtual address range within the first virtual storage device;

dynamically map a second physical address range of the physical storage device to a second virtual address range within the second virtual storage device; and

prevent access to the second physical address range from the first host.

9. The system as recited in claim 1, further comprising a first physical storage device, wherein the storage software stack includes a second layer, wherein the off-host virtualizer is further configured to:

aggregate a first set of physical storage regions within the first physical storage device into a first logical volume;

dynamically map a first range of virtual storage within the first virtual storage device to the first logical volume; and

make the first range of virtual storage accessible to the second layer for I/O operations to the first logical volume.

10. The system as recited in claim 9, wherein the off-host virtualizer is further configured to:

aggregate a second set of physical storage regions within the first physical storage device into a second logical volume;

dynamically map a second range of virtual storage within the first virtual storage device to the second logical volume; and

make the second range of virtual storage accessible to the second layer for I/O operations to the second logical volume.

11. The system as recited in claim 9, further comprising a second host, wherein the second host comprises a second storage software stack including a first layer and a second layer;

wherein the off-host virtualizer is further configured to;

present a second virtual storage device comprising one or more regions that are not initially mapped to physical storage;

make the second virtual storage device accessible to the second host;

aggregate a second set of physical storage regions within the first physical storage device into a second logical volume; and

dynamically map a second range of virtual storage within the second virtual storage device to the second logical volume;

wherein the first layer of the second storage software stack is configured to detect and access the second virtual storage device as if the second virtual storage device were mapped to physical storage, and wherein the second layer of the second storage software stack is configured to access the second range of virtual storage within the second virtual storage device for I/O operations to the second logical volume.

12. The system as recited in claim 11, wherein the off-host virtualizer is further configured to prevent the second host from performing an I/O operation on the first logical volume.

13. The system as recited in claim 11, wherein the first host is configured to access the first virtual storage device via a first storage network, wherein the second host is configured to access the second virtual storage device via a second storage network.

14. The system as recited in claim 13, wherein each storage network of the first, and second storage networks includes an independently configurable fibre channel fabric.

15. A method comprising:

presenting a first virtual storage device comprising one or more regions that are not initially mapped to physical storage;

making the first virtual storage device accessible to a first host; and

detecting and accessing the first virtual storage device from a first layer of a storage software stack at the first host as if the virtual storage device were mapped to physical storage.

16. The method as recited in claim 15, further comprising:

mapping a portion of the first virtual storage device to metadata formatted according to a requirement of an operating system in use at the first host.

17. The method as recited in claim 15, further comprising:

dynamically mapping a first region of an additional storage device to a particular region of the first virtual storage device; and

accessing the first region of the additional storage device from a second layer of the storage software stack via the first layer.

18. The method as recited in claim 15, further comprising:

dynamically mapping a first range of storage within a first physical storage device and a second range of storage within a second physical storage device to a respective address range within the first virtual storage device.

19. The method as recited in claim 15, further comprising:

aggregating a first set of physical storage regions within a first physical storage device into a first logical volume;

dynamically mapping a first range of virtual storage within the first virtual storage device to the first logical volume; and

making the first range of virtual storage accessible to a second layer of the storage software stack for I/O operations to the first logical volume.

20. A computer accessible medium comprising program instructions, wherein the instructions are executable to:

present a first virtual storage device comprising one or more regions that are not initially mapped to physical storage;

make the first virtual storage device accessible to a first host; and

detect and access the first virtual storage device from a first layer of a storage software stack at the first host as if the virtual storage device were mapped to physical storage.

21. The computer accessible medium as recited in claim 20, wherein the instructions are further executable to:

map a portion of the first virtual storage device to metadata formatted according to a requirement of an operating system in use at the first host.

22. The computer accessible medium as recited in claim 20, wherein the instructions are further executable to:

dynamically map a first region of an additional storage device to a particular region of the first virtual storage device; and

access the first region of the additional storage device from a second layer of the storage software stack via the first layer.

23. The computer accessible medium as recited in claim 20, wherein the instructions are further executable to:

dynamically map a first range of storage within a first physical storage device and a second range of storage within a second physical storage device to a respective address range within the first virtual storage device.

24. The computer accessible medium as recited in claim 20, wherein the instructions are further executable to:

aggregate a first set of physical storage regions within a first physical storage device into a first logical volume;

dynamically map a first range of virtual storage within the first virtual storage device to the first logical volume; and

make the first range of virtual storage accessible to a second layer of the storage software stack for I/O operations to the first logical volume.