Data migration method and a data migration apparatus

• US 20050193181A1
• Filed: 07/16/2004
• Published: 09/01/2005
• Est. Priority Date: 02/26/2004
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Kaneda, Yasunori, Fujita, Takahiro
• Granted Patent: US 7,107,421 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 3/0622 in relation to access
• CPC Class Codes: G06F 3/0649 Lifecycle management
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

The management computer 600 copies data in the volume 111 within the storage device 100A to the volume 115 within the storage device 100B. Upon completion of copy processing, the volume 115 is set to write protect. Then, the data in the volume 111 is read from the storage device 100A, and the data in the volume 115 is also read from the storage device 100B, to compare the two data items. Only when the data items agree with each other, setting of FC switch 400 is changed, and a target of the host computer 500 is switched from the storage device 100A to the storage device 100B. Therefore, it is possible to detect or prevent an illegal data modification in the course of data copying from the source volume to the destination volume.

Claims

1. A data migration method from a first storage device to a second storage device in a computer system including said first storage device and said second storage device which provide volumes to a host computer via a switch, comprising the steps of:

invoking to said second storage device, a request for creating a destination volume having a size identical to the size of a source volume that is provided by said first storage device, allowing said second storage device to create said destination volume;

carrying out data copy processing which stores data corresponding to data in said source volume into said destination volume;

invoking to said second storage device, a write protect request for said destination volume, and setting said destination volume as write protect, where the data in said source volume is copied;

reading out the data in said source volume from said first storage device and the data in said destination volume from said second storage device, and comparing the two data items; and

invoking a connection switching request to said switch, when it is indicated the data in said source volume agrees with the data in said destination volume, and carrying out switching of a target of said host computer, from said first storage device to said second storage device.

2. A data migration method according to claim 1, wherein,

said computer system includes a data migration apparatus, and

said data migration apparatus carries out the data migration method according to claim 1.

3. A data migration method according to claim 1, wherein,

said second storage device has an exclusive receiving function which allows a specific source to transmit a write request, and

said data migration apparatus further comprises the steps of:

invoking an exclusive receiving function setting request to said second storage device, prior to said data copy processing, and setting such that the write request is processed only when a source for transmitting the write request to said destination volume is said data migration device, and

invoking to said second storage device, an exclusive receiving function setting release request after said destination volume to which the data has been copied is set to write protect, and releasing the exclusive receiving function set to said destination volume.

4. A data migration method according to claim 2, wherein,

said second storage device comprises an authentication function which authenticates an accessing source, and

said data migration apparatus further comprises the steps of:

invoking to said second storage device an authentication function setting request prior to said data copy processing, when the accessing source to said destination volume has a predetermined authentication information, setting an authentication function so that accessing to said destination volume from the accessing source is authorized, and setting said predetermined authentication information as authentication information to be used for accessing said destination volume; and

invoking an authentication function setting release request to said second storage after executing the step which sets said destination volume to write protect, and releasing the authentication function set in said destination volume.

5. A data migration method according to claim 3, wherein,

said second storage device further comprises an authentication function which authenticates an accessing source, and

said data migration apparatus further comprises the steps of:

invoking to said second storage device an authentication function setting request prior to said data copy processing, when the accessing source to said destination volume has a predetermined authentication information, setting an authentication function so that accessing to said destination volume from the accessing source is authorized, and setting said predetermined authentication information as authentication information to be used for accessing said destination volume; and

invoking an authentication function setting release request to said second storage after executing the step which sets said destination volume to write protect, and releasing the authentication function set in said destination volume.

9. A data migration method according to claim 1, wherein,

said source volume is set to write protect.

10. A data migration method according to claim 3, wherein,

said source volume is set to write protect.

11. A data migration method according to claim 4, wherein,

said source volume is set to write protect.

12. A data migration method according to claim 5, wherein,

said source volume is set to write protect.

6. A data migration method which carries out data migration from a first storage device to a second storage device in a computer system, comprising a host computer, said first storage device and said second storage device which provide volumes to said host computer, a switch which establishes connection among said host computer, said first storage device and said second storage device, and a data migration apparatus, wherein,

said data migration apparatus comprising the steps of:

invoking to said second storage device, a request for creating a destination volume having a size identical to the size of a source volume that is provided by said first storage device;

carrying out a data copy processing which copies the data stored in said source volume to said destination volume, by repeating a processing with respect to data in said source volume from top to bottom, under a condition that a write complete notification as to data immediately before said data is received from said second storage device, said processing including, to read out data of a predetermined length from said source volume, calculate a write address in said destination volume on the basis of a total data length of the data read out so far from said source volume, and to invoke to said second storage device a request for writing the data together with a designation of the write address thus calculated; and

invoking a connection switching request to said switch and carrying out switching of a target of said host computer, from said first storage device to said second storage device, and

said second storage device comprising the steps of;

creating said destination volume in accordance with the request for creating said destination volume received from said data migration apparatus,

comparing the write address designated by the request for writing the data to said destination volume, which is received from said data migration apparatus, with a reserved write address of a new data in said destination volume determined by the total data length of already-written in said destination volume, and

executing the write request and issuing a write complete notification to said data migration apparatus if the two addresses equal to each other.

7. A data migration method according to claim 6, wherein,

if the two addresses do not equal to each other as a result of comparison, said second storage device does not execute the write request and issues an error notification to said data migration apparatus, and said data migration apparatus terminates said data copy processing.

8. A data migration method which carries out data migration from a first storage device to a second storage device in a computer system, comprising a host computer, said first storage device and said second storage device which provide volumes to said host computer, a switch which establishes connection among said host computer, said first storage device and said second storage device, and a data migration apparatus, wherein,

said switch issues a connection notification to said data migration apparatus when a new computer is connected;

and

said data migration apparatus invokes a request for creating a destination volume having a size identical to a source volume provided by said first storage device, allowing said second storage device to create said destination volume,

carries out a data copy processing which stores data corresponding to data in the source volume, into the destination volume, and

suspends said data copy processing upon receipt of said connection notification from said switch during said data copy processing.

13. A data migration apparatus which carries out data migration from a first storage device to a second storage device, comprising:

a volume creation unit which invokes to said second storage device, a request for creating a destination volume having a size identical to the size of a source volume that is provided by said first storage device, allowing said second storage device to create said destination volume;

a data copy unit which carries out data copy processing which stores data corresponding to data stored in said source volume, into said destination volume;

a write protect unit which invokes to said second storage device, a write protect request for said destination volume, and sets said destination volume to write protect, where the data in said source volume is copied;

a comparison unit which reads out the data in said source volume from said first storage device and the data in said destination volume from said second storage device, and compares the two data items; and

a connection switching unit which invokes a connection switching request to a switch, which connects said first and second storage devices with a host computer, and carries out switching of a target of said host computer, from said first storage device to said second storage device, when it is indicated the data in said source volume agrees with the data in said destination volume.

14. A storage device to which data in a source volume is copied by a data migration apparatus, comprising:

a volume creation unit which creates a destination volume having a size identical to said source volume, according to a volume creation request received from said data migration apparatus, and

a write request processing unit which compares a write address designated by a write request for writing the data to said destination volume, which is received from said data migration apparatus, with a reserved write address of a new data to said destination volume determined by a total data length of already-written in said destination volume, and if the two addresses equal to each other, executes the write request and issues a write complete notification to said data migration apparatus, and if the two addresses do not equal to each other, issues an error notification to said data migration apparatus without executing the write request.

15. A data migration apparatus which carries out data migration from a first storage device to a second storage device, comprising:

a volume creation unit which invokes a request for creating a destination volume having a size identical to a source volume provided by said first storage device, allowing said second storage device to create said destination volume;

a connection notification receive unit which receives a connection notification of a new computer from a switch connecting a host computer, said first storage device and said second storage device; and

a data copy unit which carries out a data copy processing which stores the data corresponding to data stored in said source volume, into said destination volume, and suspends said data copy processing upon receipt of said connection notification by said connection notification receive means during said data copy processing.

16. A storage device into which data in a source volume is copied, comprising:

a disk unit,

a first interface which establishes connection with an old storage device which provides said source volume,

a second interface which establishes connection with a host computer via a second route,

a switch which connects said disk unit, said first interface and said second interface,

a volume creation module which creates in said storage device, a destination volume having a size identical to the source volume provided by said old storage device,

a data copy module which carries out a data copy processing to store data corresponding to data stored in said source volume into said destination volume,

a write protect module which sets said destination volume to write protect, into which the data in said source volume has been copied,

a comparison means which reads out the data in said source volume from said old storage device and also reads out the data in said destination volume, so as to compare the two data items, and

a connection switching module which controls said switch and switches a target of said host computer from said old storage device to said disk unit, when a result of said comparison means indicates the two data items agree with each other.

17. A computer readable recording medium which stores a program allowing a data migration apparatus to carry out data migration from a first storage device to a second storage device, wherein,

said program comprises the steps of:

invokes to said second storage device, a request for creating a destination volume having a size identical to the size of a source volume that is provided by said first storage device, allowing said second storage device to create said destination volume;

carries out data copy processing which stores data corresponding to data stored in said source volume, into said destination volume;

invokes to said second storage device, a write protect request for said destination volume, and sets said destination volume to write protect, where the data in said source volume is copied;

reads out the data in said source volume from said first storage device and the data in said destination volume from said second storage device, and compares the two data items; and

invokes a connection switching request to a switch, which connects said first and second storage devices with a host computer, and carries out switching of a target of said host computer, from said first storage device to said second storage device, when it is indicated the data in said source volume agrees with the data in said destination volume.

18. A computer readable recording medium which stores a program allowing a storage device to copy data in a source volume, according to an instruction from a data migration apparatus, wherein,

said program comprises:

code that creates a destination volume having a size identical to said source volume, according to a volume creation request received from said data migration apparatus, and

code that compares a write address designated by a request for writing the data to said destination volume, which is received from said data migration apparatus, with a reserved write address of a new data to said destination volume determined by a total data length of already-written in said destination volume, and if the two addresses equal to each other, executes the write request and issues a write complete notification to said data migration apparatus, and if the two addresses do not equal to each other, issues an error notification to said data migration apparatus without executing the write request.

19. A computer readable recording medium which allows a data migration apparatus to carry out a data migration from a first storage to a second storage, wherein said program comprises:

code that invokes to said second storage device, a request for creating a destination volume having a size identical to the size of a source volume that is provided by said first storage device, allowing said second storage device to create said destination volume;

code that receives a connection notification of a new computer from a switch connecting a host computer, said first storage device and said second storage device; and

code that carries out data copy processing which stores data corresponding to data stored in said source volume, into said destination volume, and suspends said data copy processing upon receipt of said connection notification by said connection notification receive means during said data copy processing.

20. A computer system comprising a first and second storage devices, a management computer, a host computer, and a switch which connects via a network said storage devices, said management computer, and said host computer,

wherein;

each of said first and second storage devices includes an FC interface which is connected to said switch via said network, and a disk unit including at least one volume,

wherein;

a first volume provided in said first storage device stores data to be used by said host computer,

wherein;

said management computer comprises a CPU and an FC interface of said management computer, which is connected to said switch via said network,

wherein;

the CPU in said management computer transmits creation instruction information as to a second volume to said second storage device via said switch,

obtains via said switch, write property information indicating whether or not data writing from said first volume into the second volume is possible,

determines whether or not said first volume is writable based on said write property information,

when it is determined said first volume is not writable as a result of the determination, transmits to said second storage device via said FC interface, setting request information as to an access property of said second volume,

transmits a setting request as to a password to said second volume thus created,

after said password is set, carries out data copy processing from said first volume to said second volume,

after a completion of said data copy processing, transmits to said second storage device a setting request as to write protect to said second volume,

after setting said write protect, compares the data stored in said first volume and the data stored in said second volume, and

as a result of the comparison, if the two data agree with each other, transmits to said second storage device via said switch, a release request information which instructs a release of the access property and the password which are set in said second volume, and wherein;

said switch comprises an FC interface which is connected via a network with the FC interfaces respectively held by said storage devices, said management device and said host computer, a CPU, and a connection switching module which issues information received by any of said FC interfaces to another FC interface, according to an instruction from said CPU.