Storage device and method for erasing data of storage device

Patent metadata

Field	Value
Publication number	US-11360690-B2
Application number	US-201916549721-A
Country	US
Kind code	B2
Filing date	Aug 23, 2019
Priority date	Mar 6, 2019
Publication date	Jun 14, 2022
Grant date	Jun 14, 2022

Abstract

There is provided a storage device that is connected to a computer and receives an UNMAP command to cancel a relationship between a logical address and a physical address provided to the computer, in response to data deletion on the computer. The storage device includes a control unit configured to make data stored in a physical address specified by the UNMAP command irreversible.

First claim

What is claimed is:

1. A storage device connected to a computer, wherein in response to data deletion on the computer, the storage device is configured to receive an UNMAP command from the computer to cancel a relationship between a logical address and a physical address provided to the computer, the storage device comprising:
a control unit configured to:
determine whether data stored at a first physical address is allocated to at least two logical volumes in a plurality of logical volumes, wherein the first physical address is specified by the UNMAP command;
duplicate the data stored at the first physical address to a second physical address when it is determined that the data stored at the first physical address is allocated at least two logical volumes in the plurality of logical volumes;
overwrite data stored at the first physical address with random data a specified number of times, wherein this overwriting causes the data stored at the first physical address to become irreversible and thereby completely erased;
allocate the second physical address to which the data from the first physical address was duplicated to a logical volume other than a first logical volume specified by the UNMAP command.

2. The storage device according to claim 1 , wherein
the control unit has a thin provisioning function, and is configured to manage metadata in which a head address of a page in a pool, a logical volume to which the page is allocated, and a head address in the logical volume are associated with each of a plurality of pages of a specified size that constitute a pool of the thin provisioning function.

3. The storage device according to claim 2 , wherein
the control unit is configured to make the metadata related to the first physical address irreversible, wherein the first physical address is specified by the UNMAP command.

4. The storage device according to claim 2 , wherein
the control unit is configured to extract a page to be subjected to data erasing processing based on the metadata from target logical volume identification information that specifies a logical volume and a head address and the number of pages in the target logical volume, the target logical volume identification information, the head address and the number of pages being contained in the UNMAP command.

5. The storage device according to claim 1 , wherein
the control unit is configured to notify the computer that the data stored in the first physical address is in an irreversible state, wherein the first physical address is specified by the UNMAP command.

6. The storage device according to claim 1 , wherein
the storage device is provided on a hypervisor on a node.

7. A storage device connected to a computer, wherein in response to data deletion on the computer, the storage device is configured to receive an UNMAP command from the computer to cancel a relationship between a logical address and a physical address provided to the computer, the storage device comprising:
a control unit configured to:
determine whether data stored in a first physical page is allocated to at least two logical volumes of a plurality of logical volumes, wherein the first physical page is specified by the UNMAP command;
duplicate the data stored in the first physical page to a second physical page when the data stored in the first physical page is allocated to at least two logical volumes of the plurality of logical volumes;
overwrite data stored in the first physical page with random data a specified number of times, wherein this overwriting causes the data stored in the first physical page to become irreversible and thereby completely erased; and
allocate the second physical page to which the data is duplicated to a second logical volume other than a first logical volume specified by the UNMAP command.

8. The storage device according to claim 7 , wherein
the control unit has a thin provisioning function, and is configured to manage metadata in which a head address of a page in a pool, a logical volume to which the page is allocated, and a head address in the logical volume are associated with each of a plurality of pages of a specified size that constitute a pool of the thin provisioning function.

9. The storage device according to claim 7 , wherein
the control unit is configured to make metadata related to the first physical page irreversible, wherein the first physical page is specified by the UNMAP command.

10. The storage device according to claim 8 , wherein
the control unit is configured to extract a page to be subjected to data erasing processing based on the metadata from target logical volume identification information that specifies a logical volume and a head address and the number of pages in the target logical volume, the target logical volume identification information, the head address and the number of pages being contained in the UNMAP command.

11. The storage device according to claim 7 , wherein
the control unit is configured to notify the computer that the data stored in the physical the first physical is in an irreversible state, wherein the first physical page is specified by the UNMAP command.

12. The storage device according to claim 7 , wherein
the storage device is provided on a hypervisor on a node.

13. A method for erasing data of a storage device connected to a computer, the method comprising:
transmitting, via the computer, an UNMAP command to cancel a relationship between a logical address and a physical address provided to the computer in response to data deletion on the computer; and
configuring the storage device to:
receive the UNMAP command to cancel the relationship between the logical address and the physical address provided to the computer,
determine whether data stored at a first physical address is allocated to at least two logical volumes of the plurality of logical volumes, wherein the first physical address is specified by the UNMAP command,
duplicate the data stored at the first physical address to a second physical address when it is determined that the data stored at the first physical address is allocated at least two logical volumes in the plurality of logical volumes,
overwrite data stored at the first physical address with random data a specified number of times, wherein this overwriting causes the data stored at the first physical address to become irreversible and thereby completely erased, and
allocate the second physical address to which the data from the first physical address was duplicated to a logical volume other than a first logical volume specified by the UNMAP command.

14. The method for erasing data of a storage device according to claim 13 , wherein
the storage device is configured to extract a page to be subjected to data erasing processing based on metadata that manages correspondence between a logical address and a physical address from target logical volume identification information that specifies a logical volume and a head address and the number of pages in the target logical volume, the target logical volume identification information, the head address and the number of pages being contained in the UNMAP command.

15. A method for erasing data of a storage device connected to a computer, the method comprising:
transmitting, via the computer, an UNMAP command to cancel a relationship between a logical address and a physical address provided to the computer in response to data deletion on the computer; and
configuring the storage device to:
receive the UNMAP command to cancel the relationship between the logical address and the physical address provided to the co

Assignees

• Hitachi Ltd

Inventors

• Nakagawa Hirotaka
• Hara Akihiro

Classifications

• G06F3/0608 Primary

  Saving storage space on storage systems · CPC title

• G06F3/067

  Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS] · CPC title

• G06F2009/45583

  Memory management, e.g. access or allocation · CPC title

• G06F2009/45595

  Network integration; Enabling network access in virtual machine instances · CPC title

• G06F9/45558

  Hypervisor-specific management and integration aspects · CPC title