DATA VOLUME SPARSENESS

• US 20110029713A1
• Filed: 11/16/2009
• Published: 02/03/2011
• Est. Priority Date: 08/03/2009
• Status: Active Grant

• Current Assignee: Quantum Corporation (Chi Ko Investment Co., Ltd.)
• Original Assignee: Quantum Corporation (Chi Ko Investment Co., Ltd.)
• Inventors: Haile, J. Mitchell, Wade, Gregory L.
• Granted Patent: US 8,825,936 B2
• Time in Patent Office: Days
• US Class Current: 711/6
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

Disclosed is a method of operating a data storage system. The method comprises generating first metadata describing storage of a volume of data in a first storage volume, storing the volume of data within a second storage volume, generating second metadata describing storage of the volume of data in the second storage volume, and processing the first metadata and the second metadata to increase sparseness of the volume of data stored in the second storage volume.

Claims

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

generating first metadata describing storage of a volume of data in a first storage volume;

storing the volume of data within a second storage volume;

generating second metadata describing storage of the volume of data in the second storage volume; and

processing the first metadata and the second metadata to increase sparseness of the volume of data stored in the second storage volume.

2. The method of claim 1 wherein the first storage volume comprises a virtual storage device, wherein the second storage volume comprises a virtual disk file corresponding to the virtual storage device, wherein the first metadata comprises a block bitmap for the virtual storage device, and wherein the second metadata comprises a block mapping table for the virtual disk file, wherein the method further comprises:

storing the virtual disk file on a physical storage device; and

storing the block bitmap in the virtual disk file.

3. The method of claim 2 wherein the data storage system comprises:

a processing system coupled to the physical storage device;

a host operating system stored on the physical storage device and executable by the processing system;

a hypervisor executed by the processing system and configured to provide an interface between the host operating system and a virtual machine, wherein the virtual machine comprises virtual hardware, a guest operating system and a guest application;

wherein generating the volume of data comprises executing the guest application to generate the volume of data;

wherein generating the first metadata comprises executing the guest operating system to generate the block bitmap; and

wherein generating the second metadata comprises executing the hypervisor to generate the block mapping table.

4. The method of claim 3, wherein increasing the sparseness of the volume of data stored in the second storage volume using the first metadata and the second metadata comprises:

in the hypervisor;

creating a copy of the block mapping table, resulting in a new block mapping table;

creating a copy of the volume of data from the virtual disk file, resulting in a new virtual disk file, by;

for each block identified in the block mapping table, if a corresponding block in the block bitmap is allocated, then copying the data in the block to the new virtual disk file and identifying the block as allocated in the new block mapping table, and, if the corresponding block in the block bitmap is not allocated, then identifying the block as unallocated in the new block mapping table;

in the physical storage device, replacing the virtual disk file with the new virtual disk file; and

in the hypervisor, replacing the block mapping table with the new block mapping table.

5. The method of claim 1 wherein the first storage volume comprises a partitioned portion of a physical storage device, wherein the second storage volume comprises a virtual disk file corresponding to the partitioned portion, wherein the first metadata comprises a file access table for at least the partitioned portion, and wherein the second metadata comprises a block mapping table for the virtual disk file, wherein the method further comprises:

storing the virtual disk file on the physical storage device.

6. The method of claim 1 wherein processing the first metadata and the second metadata to increase the sparseness of the volume of data stored in the second storage volume comprises transforming the second storage volume from a non-sparse state to a sparse state.

7. The method of claim 1 wherein processing the first metadata and the second metadata to increase the sparseness of the volume of data stored in the second storage volume comprises transforming the second storage volume from a sparse state to a more-sparse state relative to the sparseness of the sparse state.

8. A data storage system comprising:

a processing system configured to;

generate first metadata describing storage of a volume of data in a first storage volume;

generate second metadata describing storage of the volume of data in a second storage volume; and

process the first metadata and the second metadata to increase sparseness of the volume of data stored in the second storage volume; and

a physical storage device coupled to the processing system and configured to store the second storage volume, wherein the second storage volume stores the volume of data.

9. The data storage system of claim 8 wherein the first storage volume comprises a virtual storage device, wherein the second storage volume comprises a virtual disk file corresponding to the virtual storage device, wherein the first metadata comprises a block bitmap for the virtual storage device, and wherein the second metadata comprises a block mapping table for the virtual disk file, wherein the block bitmap is stored in the virtual disk file.

10. The data storage system of claim 9 wherein the data storage system further comprises:

a host operating system stored on the physical storage device and executable by the processing system;

a hypervisor executed by the processing system and configured to provide an interface between the host operating system and a virtual machine, wherein the virtual machine comprises virtual hardware, a guest operating system and a guest application;

wherein the guest application generates the volume of data;

wherein the guest operating system generates the block bitmap; and

wherein the hypervisor generates the block mapping table.

11. A computer readable medium having program instructions stored thereon for operating a data storage system that, when executed by a processing system, direct the processing system to:

generate first metadata describing storage of a volume of data in a first storage volume;

store the volume of data within a second storage volume;

generate second metadata describing storage of the volume of data in the second storage volume; and

process the first metadata and the second metadata to increase sparseness of the volume of data stored in the second storage volume.

12. The computer readable medium of claim 11 wherein the first storage volume comprises a virtual storage device, wherein the second storage volume comprises a virtual disk file corresponding to the virtual storage device, wherein the first metadata comprises a block bitmap for the virtual storage device, and wherein the second metadata comprises a block mapping table for the virtual disk file, wherein the program instructions, when executed by the processing system, direct the processing system to:

store the virtual disk file on a physical storage device; and

store the block bitmap in the virtual disk file.

13. The computer readable medium of claim 12 wherein the data storage system comprises:

the processing system coupled to the physical storage device;

a host operating system stored on the physical storage device and executable by the processing system;

a hypervisor executed by the processing system and configured to provide an interface between the host operating system and a virtual machine, wherein the virtual machine comprises virtual hardware, a guest operating system and a guest application;

wherein the program instructions, when executed by the processing system, direct the processing system to;

execute the guest application to generate the volume of data;

execute the guest operating system to generate the block bitmap; and

execute the hypervisor to generate the block mapping table.

14. The computer readable medium of claim 13, wherein to increase the sparseness of the volume of data stored in the second storage volume using the first metadata and the second metadata, the program instructions, when executed by the processing system, direct the processing system to:

in the hypervisor;

create a copy of the block mapping table, resulting in new block mapping table;

create a copy of the volume of data from the virtual disk file, resulting in a new virtual disk file, by;

for each block identified in the block mapping table, if a corresponding block in the block bitmap is allocated, then copy the data in the block to the new virtual disk file and identify the block as allocated in the new block mapping table, and, if the corresponding block in the block bitmap is not allocated, then identify the block as unallocated in the new block mapping table;

in the physical storage device, replace the virtual disk file with the new virtual disk file; and

in the hypervisor, replace the block mapping table with the new block mapping table.

15. The computer readable medium of claim 11 wherein the first storage volume comprises a partitioned portion of a physical storage device, wherein the second storage volume comprises a virtual disk file corresponding to the partitioned portion, wherein the first metadata comprises a file access table for at least the partitioned portion, and wherein the second metadata comprises a block mapping table for the virtual disk file, wherein the program instructions, when executed by the processing system, direct the processing system to store the virtual disk file on the physical storage device.

16. The computer readable medium of claim 11 wherein, to process the first metadata and the second metadata to increase the sparseness of the volume of data stored in the second storage volume, the program instructions direct the processing system to transform the second storage volume from a non-sparse state to a sparse state.

17. The computer readable medium of claim 11 wherein, to process the first metadata and the second metadata to increase the sparseness of the volume of data stored in the second storage volume, the program instructions direct the processing system to transform the second storage volume from a sparse state to a more-sparse state relative to the sparseness of the sparse state.

18. An apparatus comprising:

a means for generating first metadata describing storage of a volume of data in a first storage volume;

a means for storing the volume of data within a second storage volume;

a means for generating second metadata describing storage of the volume of data in the second storage volume; and

a means for processing the first metadata and the second metadata to increase sparseness of the volume of data stored in the second storage volume.