Copying method between logical disks, disk-storage system and its storage medium

• US 6,757,797 B1
• Filed: 03/23/2000
• Issued: 06/29/2004
• Est. Priority Date: 09/30/1999
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Onda, Yasuhiro, Kato, Tadaomi, Kaiya, Norikazu
• Primary Examiner(s): Gossage, Glenn
• Assistant Examiner(s): DINH, NGOC V
• Application Number:
  US09/534,113
• Time in Patent Office: 1,559 Days
• Field of Search: 711/162, 711/114, 711/168
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1466 to make the backup process non-disruptive
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A copying method, disk storage system, and storage medium for copying data from one logical disk to another logical disk, making possible immediate access, in response to a copy command. Copying from a first logical disk to a second logical disk is performed for each area in a copy range, and when there is an access to either logical disk, copying is interrupted. When performing update access of an uncopied area in the first logical disk, the area is copied from the first logical disk to the second logical disk, and then the uncopied area is updated. When performing reference access of an uncopied area in the second logical disk, the corresponding area in the first logical disk is referenced. When performing update access of an uncopied area in the second logical disk, that area in the second logical disk is updated, and copying is prohibited. In this way, it is possible to access the first and second logical disks while copying is in progress, and it is possible to immediately notify a host, upon receipt of a copy instruction, that a copying has been completed.

Claims

1. A copy method for copying data from a copy-source logical disk to a copy-destination logical disk according to a copy instruction from a host, comprising:

notifying the host of a copy completion upon receipt of the copy instruction;

copying, in units of each area dividing the copy-source logical disk, from the copy-source logical disk to the copy-destination logical disk;

interrupting said copying in response to an access request;

from the host; and

allowing access to the copy-source logical disk and copy-destination logical disk according to an access request during said copying,

wherein said copying further includes;

referencing control information that indicates a copying condition of the areas, and setting control information of a next copy area; and

updating the control information for the copy area after said copying of the copy area has finished,

and wherein said allowing of access includes;

referencing the control information and determining whether a target access area of an access request is a copied area or uncopied area;

copying the target access area of the copy-source logical disk to the copy-destination logical disk and then updating the target access area of the copy-source logical disk when the access request is a request for updating an uncopied area of the copy-source logical disk; and

referencing the target access area of the copy-source logical disk when the access request is a request for referencing an uncopied area of the copy-destination logical disk, and updating the target access area of the copy-destination logical disk and prohibiting copying of data from the copy-source logical disk to the target access area when the access request is for the updating of an uncopied area of said copy-destination logical disk.

2. The copy method of claim 1, wherein said allowing of access further includes:

referencing the target access area of the copy-source logical disk when performing reference access of the copy-source logical disk; and

referencing or updating the target access area of the copy-destination logical disk when accessing copied areas of the copy-destination logical disk.

3. The copy method of claim 1, wherein said referencing of an uncopied area of the copy-destination logical disk comprises:

copying the target access area of the referenced copy-source logical disk to the copy destination logical disk after the target access area of the copy-source logical disk has been referenced.

4. The copy method of claim 1, wherein allowing of access further comprises updating the control information of the target access area after the target access area of the copy-source logical disk has been copied to the copy-destination logical disk.

5. The copy method of claim 1, wherein

said copying from the copy-source logical disk to the copy-destination logical disk further comprises referencing control information that indicates a copying condition of each of the areas of the copy-source logical disk and setting the copying condition of a next copy area, reading the target area of the copy-source logical disk to memory, updating the control information after the target area has been read, and writing the target area of the memory to the copy-destination logical disk.

6. The copy method of claim 1, wherein the copying from the copy-source logical disk to the copy-destination logical disk further comprises:

referencing a bitmap indicated by a flag that indicates a copying condition of each area and setting a copying condition for a next copy area, and

a step of updating the copy area flag of the bitmap.

7. A disk storage system, comprising:

at least one physical disk including a plurality of logical discs; and

a disk controller to access data of a copy-source logical disk according to an access instruction from a host, and to copy data, in units of each area dividing the copy-source logical disk, of the copy-source logical disk to a copy-destination logical disk, according to a copy instruction from the host,

wherein said disk controller interrupts the copying of data upon receipt of the access instruction during the copying of data and accesses the logical disk according to the access instruction,

and wherein the disk controller notifies the host of a copying completion upon the receipt of a copy instruction, performs the copying of data while referencing control information indicating a copying condition of the areas, setting a copying condition of a next copy area, and updating the control information of the areas after copying of the areas has finished,

and wherein the disk controller determines whether a target access area of the access instruction is a copied area or uncopied area based on a reference to a corresponding control information, performs a copying of the target access area of the copy-source logical disk to the copy-destination logical disk and then updates the target access area of the copy-source logical disk when the access instruction is a request for an updating of an uncopied area of the copy destination logical disk, and updates the target access area of the copy destination logical disk and prohibits copying of data from the copy-source logical disk to the target access area when the access instruction is a request for an updating of the uncopied area of the copy-destination logical disk.

8. A computer readable storage medium for storing a program for copying data from a copy-source logical disk to a copy-destination logical disk according to a copy instruction, said program executable by a computer and comprising:

instruction code notifying a host of a completion of a copying upon receipt of the copy instruction;

instruction code copying data, in units of each area dividing the copy source logical disk, from the copy-source logical disk to the copy-destination logical disk;

instruction code interrupting the copying of data in response to an access request from the host; and

instruction code for allowing an accessing of the copy-source logical disk and copy-destination logical disk according to the access request during copying,

wherein said instruction code copying of the data further includes;

instruction code referencing control information that indicates a copying condition of the areas, and determining a next copy area according to the reference result; and

instruction code updating the control information of the area after a copying of the area has finished, and wherein said instruction code allowing an accessing further includes;

instruction code determining whether a target access area of said access request is a copied area or uncopied area, based on a referencing of control information of the target access area;

instruction code copying the target access area of the copy-source logical disk to the copy-destination logical disk and then updating the target access area of the copy-source logical disk when the access request is a request for updating of an uncopied area of the copy-source logical disk,

instruction code referencing the target access area of said copy-source logical disk when the access request is a request for a referencing of an uncopied area of said copy-destination logical disk; and

instruction code updating the target access area of the copy-destination logical disk and prohibiting a copying of data from the copy-source logical disk to the target access area when the access request is a request for updating the uncopied area of said copy-destination logical disk.

9. A copy method for copying data from a copy-source logical disk to a copy-destination logical disk according to a copy instruction from a host, comprising:

notifying the host of a completion of copying upon receipt of said copy instruction;

copying data, in units of each area dividing the copy-source logical disk, from said copy-source logical disk to said copy-destination logical disk;

interrupting said copying of data in response to an access request from the host; and

allowing an accessing of the copy-source logical disk and copy-destination logical disk, upon receipt of the access request, during said copying of data;

wherein said copying of data includes;

referencing control information indicating a copying condition of the areas, and setting a copying condition of a next copy area;

reading a target area of the copy-source logical disk to a memory;

updating the control information of the target area after copying of target area has finished; and

writing data of the target area in the memory to the copy-destination logical disk,

and wherein said allowing an accessing further includes referencing the control information and determining whether a target access area of an access request is a copied area or uncopied area.

10. A disk storage system, comprising:

at least one physical disk including a logical disk; and

a disk controller to access data of a specified logical disk according to an access instruction from the host, and copying data, in units of each area dividing the copy-source logical disk, of the copy-source logical disk to the copy-destination logical disk according to a copy instruction from the host,

wherein said disk controller interrupts the copying of data upon receipt of the access instruction, during the copying of data, and accesses either the copy-source logical disk or the copy-destination logical disk according to the access instruction,

wherein said disk controller includes a controller, a memory, and a table to store information that indicates a copying condition of the areas,

wherein the controller notifies the host of a completion of copying upon receipt of the copy instruction, references control information of said table, sets a control information of a next copy area, reads a target area of the copy-source logical disk to the memory, updates the control information of the target area after copying of the target area has finished; and

writes data of the target area, in the memory, to the copy-destination logical disk, and

wherein the controller determines whether a target access area of the access request is a copied area or an uncopied area based on reference to the control information.