TAPE EMULATING DISK BASED STORAGE SYSTEM AND METHOD WITH AUTOMATICALLY RESIZED EMULATED TAPE CAPACITY

• US 20100250229A1
• Filed: 06/09/2010
• Published: 09/30/2010
• Est. Priority Date: 08/30/2004
• Status: Active Grant

• Current Assignee: Overland Storage Incorporated (Silicon Valley Technology Partners LLC)
• Original Assignee: Overland Storage Incorporated (Silicon Valley Technology Partners LLC)
• Inventors: Davies, Daniel Morgan, Reider, Michael H., Geist, Kenneth David, Matze, John E.
• Granted Patent: US 8,731,897 B2
• Time in Patent Office: Days
• US Class Current: 703/24
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• 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 3/0686 Libraries, e.g. tape libraries, jukebox
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: G11B 27/002 Programmed access in sequence to a plurality of record carriers or indexed parts, e.g. tracks, thereof, e.g. for editing; transfer of record carriers from magazine G11B15/68, G11B17/10; G11B17/22

Abstract

A data protection and storage system includes an array of disk drives for data storage. Data is received for storage on the disk drive via an interface that is configured to emulate a tape drive interface. A virtual tape data structure is created and stored on the disk drives. The allocated capacity of the virtual tape is dynamically and transparently alterable in response to data storage demand within the virtual tape.

Claims

1. A data storage system comprising:

one or more disk drives;

an interface configured to emulate a tape drive and to receive data for storage on said one or more disk drives using tape format data storage commands and tape storage data formats;

a storage controller configured to allocate a portion of the storage space on said one or more disk drives to a tape storage volume that receives data via said interface, wherein said storage controller is further configured to automatically change the amount of storage space allocated to said tape storage volume in response to tape format data storage commands received via said interface.

2. The system of claim 1 wherein said one or more disk drives and said storage controller are mounted within a common housing.

3. The system of claim 1 wherein at least one of said one or more disk drives and said storage controller are mounted in separate housings.

4. The data storage device of claim 1 wherein said interface communicates in an iSCSI or Fibre Channel format.

5. The data storage device of claim 1, wherein said storage controller is configured to decrease the amount of storage space allocated to said tape storage volume if a write command to overwrite a logical block address proximate to the first block of data is received.

6. The data storage device of claim 1, wherein said storage controller is configured to increase the amount of storage space allocated to said tape storage volume only if said increase does not place said allocated storage space above a pre-determined maximum.

7. The data storage device of claim 6, wherein said storage controller is configured to generate a warning if said increase would place said allocated storage space above said pre-determined maximum.

8. A data storage device comprising:

at least one hard disk drive;

a tape drive emulator;

at least one emulated magnetic tape having an apparent storage capacity provided by at least some of the storage capacity of said hard disk drive;

means for automatically changing the apparent storage capacity of said emulated magnetic tape in response to write commands received by said tape drive emulator.

9. The data storage device of claim 8, wherein said means for automatically changing the apparent storage capacity of said emulated magnetic tape comprises a stored value indicating an end of data sector and an early warning sector, and a storage controller configured to compare said end of data sector and early warning sector.

10. The data storage device of claim 8, wherein said emulated magnetic tape is defined by entries in a stored tape header file that includes values for a beginning of media sector and an end of media sector.

11. A data storage device of claim 10, wherein said tape header file additionally defines a value for an early warning sector.

12. A method of data storage comprising:

defining a virtual tape storage volume;

allocating an amount of storage space to said virtual tape storage volume;

automatically increasing said allocated amount in response to storing a selected amount of data in said volume.

13. The method of claim 12 additionally comprising automatically decreasing said allocated amount in response to overwriting data stored in said storage volume.

14. A method of data storage comprising:

emulating a magnetic tape using a portion of data storage capacity of one or more disk drives;

defining an end of data sector value and an end of media sector value for said emulated magnetic tape;

increasing said end of media sector value if said end of data sector exceeds a selected value.

15. The method of claim 14, comprising:

defining an early warning sector value;

comparing said end of data sector value with said early warning sector value; and

increasing both said early warning sector value and said end of media sector value if said end of data sector value equals or exceeds said warning sector value.

16. A data storage system comprising:

an appliance having a set of disk drives integral to or attached thereto, said appliance being configured to interface with a host system using tape drive commands and tape data formats, said appliance being configured to store data received via said interface on one or more of said set of disk drives;

a plurality of data storage volumes, wherein each volume is allocated a portion of a pool of storage space, and wherein at least one of said volumes is an emulated tape volume;

means for automatically changing at least said emulated tape volumes'"'"' allocated share of said pool in response to demand for storage space in at least some of said volumes.