SYSTEMS AND METHODS OF DATA STORAGE MANAGEMENT, SUCH AS PRE-ALLOCATION OF STORAGE SPACE

• US 20080288738A1
• Filed: 12/21/2007
• Published: 11/20/2008
• Est. Priority Date: 12/22/2006
• Status: Active Grant

• Current Assignee: CommVault Systems Incorporated
• Original Assignee: CommVault Systems Incorporated
• Inventors: Gokhale, Parag, Klose, Michael F.
• Granted Patent: US 7,831,766 B2
• Time in Patent Office: Days
• US Class Current: 711/171
• CPC Class Codes: G06F 16/13 File access structures, e.g. distributed indices arrangements of input from, or output to, record carriers G06F3/06
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0683 Plurality of storage devices

Abstract

A system and method for pre-allocating space on a storage medium is described. In some cases, the system receives two or more data items to be stored on a storage medium, pre-allocates a single, contiguous block of space on the medium, and stores the two or more data items within the single, contiguous block of space.

Claims

1. A method of transferring data from a file system to a data storage medium, the method comprising:

receiving data to be transferred to the storage medium, wherein the data to be transferred includes multiple individual jobs or files, and wherein the storage medium is managed by a disk file system;

determining an estimated amount of space on the storage medium based at least in part on the data to be transferred, wherein the determining includes estimating a size of the data to be transferred; and

allocating the estimated amount of space on the storage medium before transferring the data to the storage medium, wherein the allocated estimated amount of space is substantially contiguous on the storage medium.

2. The method of claim 1, further comprising:

determining that the allocated amount of space is greater than an amount of data transferred to the allocated space; and

freeing space not containing transferred data from the allocated space.

3. The method of claim 1, further comprising:

determining that the allocated amount of space is not sufficient to contain an amount of data transferred to the allocated space; and

expanding the allocated space in order to store the transferred amount of data within the allocated space, wherein the expanded space includes additional space contiguous with the allocated space.

4. The method of claim 1, wherein determining the estimated amount of space is based on an estimated total size of the data to be transferred.

5. The method of claim 1, wherein determining the estimated amount of space is based at least in part on an amount of available space contained on the storage medium.

6. The method of claim 1, wherein allocating the estimated amount of space includes reserving consecutive data blocks on the storage medium.

7. The method of claim 1, further comprising:

creating a data structure that contains information referencing the transferred data within the allocated space.

8. A system for transferring two or more data items to a storage device by way of a file system, comprising:

a data allocation component, wherein the data allocation component reserves space on the storage device before the two or more data items are transferred to the storage device, wherein the data allocation component reserves the space on the storage device as if a single data item is to be stored, and wherein the file system would have allocated two or more discrete areas of the storage device but for the data allocation component; and

a data transfer component, in communication with the data allocation component, wherein the data transfer component transfers the two or more data items from the file system to the reserved space on the storage device.

9. The system of claim 8, further comprising:

a data reference component, wherein the data reference component creates a data structure that references locations of the two or more data items within the reserved space.

10. The system of claim 8, further comprising:

a data estimation component, wherein the data estimation component determines an amount of space of the storage device to reserve based at least in part on characteristics of the two or more data items received by the data transfer component.

11. The system of claim 8, further comprising:

a data estimation component, wherein the data estimation component determines an amount of space of the storage device to reserve based at least in part on the two or more data items received by the data transfer component and on space on the storage device that does not already contain data items.

12. The system of claim 8, wherein the data allocation component frees any unused space from the reserved space after the data transfer component transfers the two or more data items from the file system to the storage device.

13. The system of claim 8, wherein the data allocation component allocates additional space to the reserved space when the reserved space in full and the data transfer component has not transferred all the data items from the file system to the storage device.

14. A method of reducing fragmentation in a data storage device used in a data storage operation, the method comprising:

allocating a predetermined amount of consecutive blocks on the data storage device by calculating an amount of consecutive blocks of needed storage space for multiple discrete data files or jobs and allocating a predetermined amount of consecutive blocks greater than the calculated amount; and

storing two or more distinct groups of data within the allocated blocks of the data storage device.

15. The method of claim 14, further comprising:

determining the predetermined amount of consecutive blocks based on the amount of data within the two or more distinct groups of data to be stored on the data storage device.

16. The method of claim 14, further comprising:

freeing any blocks not used when storing the two or more distinct groups of data.

17. A method for storing data to a data storage medium, the method comprising:

receiving data to be stored on the data storage medium;

determining an estimated amount of storage space needed for the received data;

pre-allocating more than the estimated amount of storage space on the data storage medium;

transferring the data to be stored to the pre-allocated space on the data storage medium; and

removing any space not containing transferred data from the pre-allocated space.

18. The method of claim 17, further comprising:

creating a data structure representing the pre-allocated space, wherein the data structure stores information referencing the data within the pre-allocated space.

19. The method of claim 17, wherein pre-allocating more than the estimated amount of storage space on the data storage medium includes pre-allocating two discrete locations within the data storage medium.

20. A computer-readable medium whose contents cause a data storage system to perform a method of storing data to a disk-based data storage medium, the method comprising:

receiving data to be stored to a disk-based data storage medium;

estimating an amount of space required to store the received data;

identifying a location on the disk-based data storage medium having available space;

determining if the identified location contains an amount of available space equal to or larger than the estimated amount of space required to store the received data; and

when the identified location does contain an amount of available space equal to or larger than the estimated amount of space required to store the received data, transferring the received data to the identified location; and

when the identified location does not contain an amount of available space equal to or larger than the estimated amount of space required to store the received data,

examining characteristics of the received data;

selecting a subset of the received data based on the examined characteristics; and

transferring the selected subset of the received data to the identified location.

21. The computer-readable medium of claim 20, wherein selecting a subset of the received data based on the examined characteristics includes selecting data encrypted with a same security key.