Data migration method using storage area network

• US 6,976,103 B1
• Filed: 08/23/2000
• Issued: 12/13/2005
• Est. Priority Date: 03/03/2000
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Watanabe, Naoki, Takamoto, Yoshifumi
• Primary Examiner(s): Huynh, Kim
• Assistant Examiner(s): Casiano, Angel L.
• Application Number:
  US09/644,064
• Time in Patent Office: 1,938 Days
• Field of Search: 711/115, 711/149, 711/5, 711/100, 710/65, 710/21, 710/4, 710/74, 709/321, 709/4, 709/213, 709/203, 709/223
• US Class Current: 710/74
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

A new disk system is connected to a switch that has been already connected to a host and old disk system. At that time, the new disk system is assigned in advance a port ID of the same value as the port ID that has been assigned to the F_—Port of the switch, so that the new disk system will not be recognized from host 101. The new disk system read the configuration information of the old disk system. Then, in the switch, physical port ID 602 of old disk system 103 and physical port ID 602 of new disk system 104 are exchanged. The new disk system constructs volumes corresponding to the logical volume numbers and sizes of those volumes in the old disk system, and stores data of the old disk system in the corresponding volumes.

Claims

1. A method of migrating data from a first storage system, which is connected to a switch by a first communication channel and receives read/write requests from a host computer connected to the switch by a second communication channel, to a second storage system, said method comprising the steps of:

connecting the second storage system to the switch by a third communication channel;

assigning a logical identifier to the third communication channel connected to the second storage system;

changing the logical identifier assigned to the third communication channel connected to the second storage system into another logical identifier previously assigned to the first communication channel connected to the first storage system; and

writing, via the switch, data stored in the first storage system to the second storage system using said another logical identifier,

wherein the logical identifier is a renumbered identifier of a physical identifier of the third communication channel and the another logical identifier is a renumbered identifier of a physical identifier of the first communication channel.

2. A data migration method according to claim 1, wherein the first communication channel connecting between the switch and the first storage system, the third communication channel connecting between the switch and the second storage system, and the second communication channel connecting between the switch and the host computer are fiber channels.

3. A method of migrating data from a first storage system, which is connected to a switch by a first communication channel and receives read/write requests from a host computer connected to the switch by a second communication channel, to a second storage system, said method comprising the steps of:

connecting the second storage system to the switch by a third communication channel;

assigning a logical identifier to the third communication channel connected to the second storage system;

reading the number of logical volumes constructed in the first storage system and their sizes;

constructing the same number and sizes of logical volumes in the second storage system as have been constructed in the first storage system;

changing the logical identifier assigned to the third communication channel connected to the second storage system into another logical identifier previously assigned to the first communication channel connected to the first storage system; and

writing, via the switch, data stored in the first storage system to the second storage system in volume units using said another logical identifier,

wherein the logical identifier is a renumbered identifier of a physical identifier of the third communication channel and the another logical identifier is a renumbered identifier of a physical identifier of the first communication channel.

4. A method of migrating data from a first storage system, which is connected to one port of a switch provided with a plurality of ports each assigned its own physical port identifier by a first communication channel and receives, via the switch, read/write requests from a host computer connected to another port of said switch by a second communication channel, to a second storage, the method comprising the steps of:

connecting the second storage system, by a third communication channel, to a port of said switch other than the ports connected to the first storage system and the host computer;

assigning a logical port identifier to the port connected to the second storage system;

changing the logical port identifier assigned to the port connected to the second storage system into another logical port identifier previously assigned to the port connected to the first storage system;

writing the data in the first storage system to the second storage system via the switch;

if, from said host computer, there is a read or write request including said another logical port identifier assigned to the port connected to the first storage system for the first storage system, then sending the request to the second storage system; and

,

if the data for the read or write request has been written already to the second storage system, then performing read or write processing of the already written data by the second storage system, and if the data for the read or write request has not yet been written to the second storage system, then writing the data for the read or write request to the second storage system, and performing read or write processing of the written data by the second storage system using said another identifier,

wherein the logical port identifier is a renumbered identifier of a physical port identifier of the port connected to the second storage system and the another logical port identifier is a renumbered identifier of a physical port identifier of the port connected to the first storage system.

5. A data migration method according to claim 4, further comprising the steps of:

directly connecting the first storage system and the second storage system by a fourth communication channel; and

,

without passing through the switch, writing data in the first storage system to the second storage system via the fourth communication channel that directly connects the first storage system and the second storage system.

6. A data migration method of migrating data from a first storage system, which is connected to one port of a switch provided with a plurality of ports each assigned its own physical port identifier by a first communication channel and receives, via the switch, read/write requests from a host computer connected to another port of said switch by a second communication channel, to a second storage system, the method comprising the steps of:

connecting the second storage system to a port of the switch other than the ports connected to the first storage system and to the host computer by a third communication channel;

assigning a logical port identifier to the port connected to the second storage system;

exchanging the logical port identifier assigned to the port connected to the second storage system into another logical port identifier previously assigned to the port connected to the first storage system;

reading information on logical volumes constructed in the first storage system;

constructing the same number and same sizes of logical volumes in the second storage system as have been constructed in the first storage system;

writing data stored in the first storage system to the second storage system via the switch;

managing completion of said writing from the first storage system to the second storage system in volume units;

if, from said host computer, there is a read or write request including said another logical port identifier assigned to the port connected to the first storage system for the first storage system, then sending the request to the second storage system; and

if the data for the read or write request has been written already to the second storage system, then performing read or write processing of the already written data by the second storage system, and if the data for the read or write request has not yet been written to the second storage system, then writing the data for the read or write request to the second storage system, and performing read or write processing of the written data by the second storage system using said another identifier,

wherein the logical port identifier is a renumbered identifier of a physical port identifier of the port connected to the second storage system and the another logical port identifier is a renumbered identifier of a physical port identifier of the port connected to the first storage system.

7. A data migration method according to claim 6, wherein the second storage system reads, via the switch, the logical volume information from the first storage system, and manages the completion of said writing to the second storage system in volume units.

8. A data migration method according to claim 6, wherein the switch reads the logical volume information from the first storage system, constructs the same number and sizes of logical volumes in the second storage system as have been constructed in the first storage system, and manages the completion of said writing to the second storage system in volume units.

9. A data migration method according to claim 6, wherein an information processing unit connected to the switch reads the logical volume information from the first storage system, constructs the same number and sizes of logical volumes in the second storage system as have been constructed in the first storage system, and manages the completion of said writing to the second storage system in volume units.

10. A data migration method according to claim 6, wherein the second storage system reads, via the switch, the logical volume information from the first storage system, and manages the completion of said writing to the second storage system in volume units.

11. A data migration method of migrating data from a first storage system, which is connected to one port of a switch provided with a plurality of ports each assigned its own physical port identifier by a first communication channel and receives, via the switch, read/write requests from a host computer connected to another port of said switch by a second communication channel, to a second storage system, the method comprising the steps of:

connecting the second storage system to a port of the switch other than the ports connected to the first storage system and to the host computer, by a third communication channel,

wherein the port connected to the second store system being assigned a logical port identifier and a port connected to the first storage system being assigned another logical port identifier;

switching the destination of a read/write request from the host computer including information designating the first storage system as a destination from the first storage system to the second storage system by the switch by exchanging the logical port identifier assigned to the port connected to the second storage system with the another logical port identifier previously assigned to the port connected to the first storage system;

writing data in the first storage system to the second storage system via the switch; and

if the data for a read or write request from the host computer has been written already to the second storage system, then performing read or write processing of the already written data by the second storage system, and if the data for the read or write request has not yet been written to the second storage system, then writing the data for the read or write request to the second storage system, and performing read or write processing of the written data by said second storage system,

wherein the logical port identifier is a renumbered identifier of a physical port identifier of the port connected to the second storage system and the another logical port identifier is a renumbered identifier of a physical port identifier of the port connected to the first storage system.

12. A data migration method according to claim 11, further comprising the steps of:

reading the number of logical volumes constructed in the first storage system and their sizes;

constructing the same number and sizes of logical volumes in the second storage system as have been constructed in the first storage system; and

,

writing, in volume units, data stored in the first storage system to the second storage system via the switch.

13. A data migration method according to claim 12, wherein the second storage system manages completion of said writing to the second storage system in volume units.

14. A system comprising:

a switch including a plurality of ports each assigned its own physical port identifier;

a first storage system connected to a first port of the plurality of ports by a first communication channel;

a second storage system connectable to a second port of the plurality of ports by a second communication channel; and

a host computer connected to a third port of the plurality of ports by a third communication channel,

wherein said switch assigns a logical port identifier to the second port connected to the second storage system when the second storage system is connected to the switch, changes the logical port identifier assigned to the second port connected to the second storage system into another logical port identifier already assigned to the first port connected to the first storage system, transfers the data stored in the first storage system to the second storage system, and if, from the host computer, there is a read or write request including the another logical port identifier assigned to the first port connected to the first storage system for the first storage system, sends the request to the second storage system,

wherein the second storage system performs read or write processing if the data for the read or write request has been written already to the second storage system, and

wherein the switch transfers data and the second storage system performs read or write request after data transfer if the data for the read or write request has not yet been written to the second storage system,

wherein the logical port identifier is a renumbered identifier of a physical port identifier of the second port connected to the second storage system and the another logical port identifier is a renumbered identifier of a physical port identifier of the first port connected to the first storage system.

15. A method of migrating data from a first storage system, which is connected to a switch by a first communication channel and receives read/write requests from a host computer connected to the switch by a second communication channel, to a second storage system, said method comprising the steps of:

connecting the second storage system to the switch by a third communication channel;

assigning an identifier to the second storage system;

reading, by the switch from the first storage system, configuration information including the number of logical volumes constructed in the first storage system and their sizes;

transferring, by the switch, said configuration information read from the first storage system to the second storage system;

constructing, by the second storage system, the same number and sizes of logical volumes in the second storage system as have been constructed in the first storage system according to said configuration information transferred from the switch;

changing the identifier assigned to the second storage system into another identifier previously assigned to the first storage system; and

writing, via the switch, data stored in the first storage system to the second storage system in volume units using said another identifier.

16. A method of migrating data from a first storage system, which is connected to one port of a switch provided with a plurality of ports each assigned its own physical port identifier by a first communication channel and receives, via the switch, read/write requests from a host computer connected to another port of said switch by a second communication channel, to a second storage, the method comprising the steps of:

connecting the second storage system, by a third communication channel to a port of said switch other than the ports connected to the first storage system and the host computer;

assigning a logical port identifier to the port connected to the second storage system;

changing the logical port identifier assigned to the port connected to the second storage system into another logical port identifier previously assigned to the port connected to the first storage system;

writing the data in the first storage system to the second storage system via the switch;

if, from said host computer, there is a read or write request including said another logical port identifier assigned to the port connected to the first storage system for the first storage system, then sending the request to the second storage system; and

,

if the data for the read or write request has been written already to the second storage system, then performing read or write processing of the already written data by the second storage system, and if the data for the read or write request has not yet been written to the second storage system, then writing the data for the read or write request to the second storage system, and performing read or write processing of the written data by the second storage system using said another identifier,

wherein said switch reads configuration information defining a configuration of the first storage system from the first storage system and transfers said configuration information read from the first storage system to the second storage system, and

wherein the second storage system sets a configuration thereof based at least in part on said configuration information transferred from the switch.

17. A data migration method according to claim 16, further comprising the steps of:

directly connecting the first storage system and the second storage system by a fourth communication channel; and

,

without passing through the switch, writing data in the first storage system to the second storage system via the fourth communication channel that directly connects the first storage system and the second storage system.

18. A data migration method of migrating data from a first storage system, which is connected to one port of a switch provided with a plurality of ports each assigned its own physical port identifier by a first communication channel and receives, via the switch, read/write requests from a host computer connected to another port of said switch by a second communication channel, to a second storage system, the method comprising the steps of:

connecting ‘

the second storage system to a port of the switch other than the ports connected to the first storage system and to the host computer by a third communication channel;

assigning a logical port identifier to the port connected to the second storage system;

exchanging the logical port identifier assigned to the port connected to the second storage system into another logical port identifier previously assigned to the port connected to the first storage system;

reading, by the switch from the first storage system, configuration information including information on logical volumes constructed in the first storage system;

transferring, by the switch, said configuration information read from the first storage system to the second storage system;

constructing, by the second storage system, the same number and same sizes of logical volumes in the second storage system as have been constructed in the first storage system according to said configuration information transferred from the switch;

writing data stored in the first storage system to the second storage system via the switch;

managing completion of said writing from the first storage system to the second storage system in volume units;

if, from said host computer, there is a read or write request including said another logical port identifier assigned to the port connected to the first storage system for the first storage system, then sending the request to the second storage system; and

if the data for the read or write request has been written already to the second storage system, then performing read or write processing of the already written data by the second storage system, and if the data for the read or write request has not yet been written to the second storage system, then writing the data for the read or write request to the second storage system, and performing read or write processing of the written data by the second storage system using said another identifier.

19. A data migration method according to claim 18, wherein the switch reads the logical volume information from the first storage system, constructs the same number and sizes of logical volumes in the second storage system as have been constructed in the first storage system, and manages the completion of said writing to the second storage system in volume units.

20. A data migration method according to claim 18, wherein an information processing unit connected to the switch reads the logical volume information from the first storage system, constructs the same number and sizes of logical volumes in the second storage system as have been constructed in the first storage system, and manages the completion of said writing to the second storage system in volume units.

21. A data migration method of migrating data from a first storage system, which is connected to one port of a switch provided with a plurality of ports each assigned its own physical port identifier by a first communication channel and receives, via the switch, read/write requests from a host computer connected to another port of said switch by a second communication channel, to a second storage system, the method comprising the steps of:

connecting the second storage system to a port of the switch other than the ports connected to the first storage system and to the host computer, by a third communication channel;

switching the destination of a read/write request from the host computer including information designating the first storage system as a destination from the first storage system to the second storage system by the switch;

writing data in the first storage system to the second storage system via the switch; and

if the data for a read or write request from the host computer has been written already to the second storage system, then performing read or write processing of the already written data by the second storage system, and if the data for the read or write request has not yet been written to the second storage system, then writing the data for the read or write request to the second storage system, and performing read or write processing of the written data by said second storage system,

wherein said switch reads configuration information defining a configuration of the first storage system from the first storage system and transfers said configuration information read from the first storage system to the second storage system, and

wherein the second storage system sets a configuration thereof based at least in part on said configuration information transferred from the switch.

22. A data migration method according to claim 21, further comprising the steps of:

reading the number of logical volumes constructed in the first storage system and their sizes;

constructing the same number and sizes of logical volumes in the second storage system as have been constructed in the first storage system; and

,

writing, in volume units, data stored in the first storage system to the second storage system via the switch.

23. A data migration method according to claim 22, wherein the second storage system manages completion of said writing to the second storage system in volume units.

24. A system comprising:

a switch including a plurality of ports each assigned its own physical port identifier;

a first storage system connected to a first port of the plurality of ports by a first communication channel;

a second storage system connectable to a second port of the plurality of ports by a second communication channel; and

a host computer connected to a third port of the plurality of ports by a third communication channel,

wherein said switch assigns a logical port identifier to the second port connected to the second storage system when the second storage system is connected to the switch, changes the logical port identifier assigned to the second port connected to the second storage system into another logical port identifier already assigned to the first port connected to the first storage system, transfers the data stored in the first storage system to the second storage system, and if, from the host computer, there is a read or write request including the another logical port identifier assigned to the first port connected to the first storage system for the first storage system, sends the request to the second storage system,

wherein the second storage system performs read or write processing if the data for the read or write request has been written already to the second storage system, and

wherein the switch transfers data and the second storage system performs read or write request after data transfer if the data for the read or write request has not yet been written to the second storage system,

wherein said switch reads configuration information defining a configuration of the first storage system from the first storage system and transfers said configuration information read from the first storage system to the second storage system, and

wherein the second storage system sets a configuration thereof based at least in part on said configuration information transferred from the switch.