Automated on-line capacity expansion method for storage device

• US 20050091455A1
• Filed: 11/19/2004
• Published: 04/28/2005
• Est. Priority Date: 07/05/2001
• Status: Active Grant

• Current Assignee: Kouji Arai, Manabu Kitamura, Yoshiki Kano
• Original Assignee: Kouji Arai, Manabu Kitamura, Yoshiki Kano
• Inventors: Kitamura, Manabu, Kano, Yoshiki, Arai, Kouji
• Granted Patent: US 7,447,832 B2
• Time in Patent Office: Days
• US Class Current: 711/114
• 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 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A volume provider unit in a computer system that detects a logical block address of a read or write I/O accessing a logical volume of a storage device from a host. According to the logical block address fetched, a storage domain of the logical volume is dynamically expanded. Moreover, the storage domain of the logical volume is reduced or expanded according to an instruction of logical volume capacity reduction or expansion from a host commander part to a volume server.

Claims

1. A system for storing data accessed from a host, comprising:

a plurality of disk devices, the plurality of disk devices storing data;

an Input/Output (I/O) detector, the I/O detector accepting an I/O request to a logical volume from a host, the capacity of said logical volume managed by an operating system (OS) in a host being larger than a capacity of a physical storage area actually allocated to said logical volume;

an I/O processor, said I/O processor performing an I/O process according to said I/O request;

a capacity controller, the capacity controller allocating a physical storage area to a logical volume, said capacity controller allocating an additional physical storage area to said logical volume according to said I/O request when said I/O detector receives an I/O request to a logical volume whose capacity is larger than a capacity of physical storage area actually allocated to said logical volume;

a segment manager, the segment manager managing a storage domain of the logical volume; and

a physical and logical address manager, the physical and logical address manager receiving a request from the capacity controller and reserving a free segment in response to the request,

wherein if the physical and logical address manager receives a request to connect segment from the capacity controller, the physical and logical address manager connects the reserved segment to the logical volume in response to the connect segment request.

2. The system according to claim 1, further comprising a segment management table residing in the segment manager.

3. The system according to claim 2, the segment management table containing information related to at least one of a disk ID, a segment number, a starting logical block address, a segment size, and an in-use state value.

4. The system according to claim 1, further comprising a physical and logical management table residing in the physical and logical address manager.

5. The system according to claim 4, the physical and logical management table containing information related to at least one of a logical unit number, a segment number, a starting logical unit number logical block address, and an ending logical unit number logical block address.

6. A method for storing data comprising:

storing data by a plurality of disk devices;

accepting an I/O request to a logical volume from a host by an Input/Output (I/O) detector, the capacity of said logical volume managed by an operating system (OS) in a host being larger than a capacity of a physical storage area actually allocated to said logical volume; and

performing an I/O process according to said I/O request by an I/O processor.

7. The method according to claim 6, further comprising allocating a physical storage area to a logical volume by a capacity controller, said capacity controller allocating an additional physical storage area to said logical volume according to said I/O request when said I/O detector receives an I/O request to a logical volume whose capacity is larger than a capacity of physical storage area actually allocated to said logical volume.

8. The method according to claim 7, further comprising returning an error by said capacity controller when an additional physical storage area for allocating to said logical volume does not exist.

9. The method according to claim 7, further comprising interpreting a logical block address of an access target included in said I/O request and deciding whether a physical storage area corresponding to said logical block address is actually allocated to said logical volume or not by said I/O detector, said capacity controller allocating an additional physical storage area to said logical volume if a physical storage area corresponding to said logical block address is not actually allocated to said logical volume.

10. The method according to claim 9, writing data to said additional physical storage area according to said I/O request by said I/O processor.

11. A method for storing data comprising:

storing data by a plurality of disk devices; and

executing a capacity reduction process of a logical volume by a capacity controller,

wherein said capacity controller receives a capacity reduction request including a reduction size of storage area from a host computer, selects a physical storage area to be deleted from a logical volume according to said reduction size, deletes the selected physical storage area from the logical volume creating a capacity reduced logical volume, and calculates an end logical block address of the capacity reduced logical volume according to said reduction size.

12. A method for storing data comprising:

storing data by a plurality of disk devices;

accepting an I/O request to a logical volume from a host by an Input/Output (I/O) detector, the capacity of said logical volume managed by an operating system (OS) in a host being larger than a capacity of a physical storage area actually allocated to said logical volume;

performing an I/O process according to said I/O request by an I/O processor;

allocating a physical storage area to a logical volume by a capacity controller, said capacity controller allocating an additional physical storage area to said logical volume according to said I/O request when said I/O detector receives an I/O request to a logical volume whose capacity is larger than a capacity of physical storage area actually allocated to said logical volume;

managing a storage domain of the logical volume by a segment manager; and

receiving a request from the capacity controller and reserving a free segment in response to the request, by a physical and logical address manager,

wherein if the physical and logical address manager receives a request to connect segment from the capacity controller, the physical and logical address manager connects the reserved segment to the logical volume in response to the connect segment request.

13. The method according to claim 12, further comprising a segment management table residing in the segment manager, the segment manager controlling updating of an in-use flag in the segment management table.

14. The method according to claim 13, the segment management table containing information related to at least one of a disk ID, a segment number, a starting logical block address, a segment size, and an in-use state value.

15. The method according to claim 12, further comprising a physical and logical management table residing in the physical and logical address manager, the physical and logical address manager controlling updating of the physical and logical management table.

16. The method according to claim 15, the physical and logical management table containing information related to at least one of a logical unit number, a segment number, a starting logical unit number logical block address, and an ending logical unit number logical block address.