Methods of migrating data between storage apparatuses

• US 7,386,552 B2
• Filed: 09/25/2002
• Issued: 06/10/2008
• Est. Priority Date: 12/06/2001
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kitamura, Manabu, Takamoto, Kenichi
• Primary Examiner(s): Breene; John
• Assistant Examiner(s): Ly; Anh
• Application Number:
  US10/254,619
• Publication Number:
  US 20030110237A1
• Time in Patent Office: 2,085 Days
• Field of Search: 707/10, 707204-205, 707/200, 707/202, 707/104.1, 707100-102, 709217-219, 709/203, 709223-230, 711/112, 711/114, 711/161, 710/74
• US Class Current: 1/1
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A data migration system is provided for migrating data between an existing file server apparatus and a new file server apparatus in a computer system that includes a plurality of host computers and a plurality of file server apparatuses that are mutually connected to one another. The data migration system on the new file server apparatus copies file attributes unique to the network attached storage (NFS) and file attributes unique to the common internet file system (CIFS) from the existing file server apparatus, and stores the file attributes without changing the file attributes in the new file server apparatus. Then actual data is moved from the existing file server to the new file server. When a file access to data is made from a host computer during the file migration process, and if the data has not been migrated from the existing file server to the new file server, the data is read out from the existing file server onto the new file server, and the file access is processed by the new file server as if the existing file server were processing the file access.

Claims

1. A first file server in a computer system including at least a host computer and a second file sever, comprising:

a migration module that reads data and attribute information of at least one file stored in the second file server; and

a second module that operates to store the data and the attribute information of the at least one file read out from the second file server in the first file server without changing contents of the attribute information,

wherein the migration module obtains the attribute information of a directory of the second file server using NFS command and CIFS command, and verifying whether files exist under the directory,

wherein if any files exist, the migration module acquires a NFS attribute information for each of the files under the directory, and acquires a CIFS attribute information for each of the files under the directory, and

wherein when the host computer reads the at least one file after the second module stored the at least one file in first file server, the at least one file stored in the first file server is read.

2. The computer system including the first file server according to claim 1,

wherein the attribute information of the file includes at least date when the file is created, date when the file is referred, and date when the file is updated.

3. A file migration method for migrating data in a computer system including at least one computer, and a plurality of file servers each having a storage device, the file migration method comprising:

obtaining by a migration module attribute information of a directory of a first file server using NFS command and CIFS command;

verifying by the migration module whether files exist under the directory,

wherein if any files exist,

obtaining by the migration module a NFS attribute information for files under the directory, and

obtaining by the migration module a CIFS attribute information for files under the directory is obtained;

storing the obtained attribute information in a storage device of a second file server; and

storing in the storage device of the second file server actual data of the file read from the storage device of the first file server according to the attribute information of the file.

4. The file migration method according to claim 3, wherein the attribute information of the file includes at least one of date when the file is created, date when the file is referred, and date when the file is updated, which are stored in the storage device of the first file server.

5. The file migration method according to claim 3, wherein when the computer issues an access request to access a file that is being migrated while at least one of attribute information of the file and actual data of the file is being migrated, a content of the access request is stored in a log region of the second file server, and a process according to the content stored in the log region is performed after the file has been migrated.

6. The file migration method according to claim 3, wherein the second file server accommodates at least one file access protocol, and

attribute information of the file is stored according to each of the at least one file access protocol.

7. The file migration method according to claim 6, wherein the second file server accommodates a plurality of file access protocols, and attribute information of the file is stored according to each of the plurality of file access protocols.

8. The file migration method according to claim 3, wherein the first file server is an existing file server and the second file server is a new file server, and files stored in the existing file server are migrated to the new file server.

9. A file migration method for migrating data in a computer system including at least one host computer, an existing first file server and a new second file server, each of the first file server and the second file server having a storage device, the file migration method comprising:

obtaining by a migration module attribute information of a directory of a first file server using NFS command and CIFS command;

verifying by the migration module whether files exist under the directory,

wherein if any files exist,

obtaining by the migration module a NFS attribute information for files under the directory, and

obtaining by the migration module a CIFS attribute information for files under the directory is obtained;

obtaining actual data of files from the storage device of the first file server and storing in the storage device of the second file server the actual data of the files read from the storage device of the first file server according to the attribute information stored in the storage device of the second file server.

10. The file migration method according to claim 9, further comprising, after the steps of the step of reading the attribute information of the directory, the step of reading attribute information of the files from the storage device of the first file server according to the first file access protocol and the second file access protocol.

11. The file migration method according to claim 10, wherein the steps of storing the actual data of the files from the storage device of the first server according to the first file access protocol and the second file access protocol are conducted after the steps of reading the attribute information of the files according to the first file access protocol are completed.

12. The file migration method according to claim 10, wherein the actual data of the files are stored in the storage device of the second file server after all the attribute information are stored in the storage device of the second file server.

13. The file migration method according to claim 10, wherein the attribute information of the files includes at least one of date when the files are created, date when the files are referred, and date when the files are updated, which are stored in the storage device of the first file server.

14. The file migration method according to claim 10, wherein when the host computer issues an access request to access a file that is being migrated while at least one of attribute information of the file and actual data of the file is being migrated, a content of the access request is stored in a log region of the storage device of the second file server, and a process according to the content stored in the log region is performed after the file has been migrated from the first file server to the second file server.

15. The migration method according to claim 9, further comprising the step of reading attribute information of subdirectories under the directory according to the first file access protocol and storing the read attribute information of the subdirectories in the storage device of the second file server.

16. The migration method according to claim 9, further comprising the step of reading attribute information of subdirectories under the directory according to the second file access protocol and storing the read attribute information of the subdirectories in the storage device of the second file server.

17. A file migration method for migrating date in a computer system including at least one host computer and at least one existing file server, the file migration method comprising the steps of:

disconnecting the existing file server from the computer system;

adding a new file server and connecting the existing file server to the new file server;

obtaining by a migration module attribute information of a directory of the existing server using NFS command and CIFS command;

verifying by the migration module whether files exist under a directory,

wherein if any files exist,

obtaining by the migration module a NFS attribute information for files under the directory, and

obtaining by the migration module a CIFS attribute information for files under the directory is obtained;

reading out a directory tree structure of the existing file server and storing the directory tree structure in the new file server;

reading out all data files in the existing file server and successively writing the data files into the new file server according to the directory tree structure.

18. The file migration method according to claim 17, wherein the step of reading out the directory tree structure includes the steps of reading out attribute information for files from the existing file server and writing the attribute information into the new file server without changing the attribute information.

19. The file migration method according to claim 18, wherein the attribute information of the files includes at least one of date when the files are created, date when the files are referred, and date when the files are updated, which are stored in the storage device of the existing file server.

20. The file migration method according to claim 19, wherein when the host computer issues an access request to access a file that is being migrated while at least one of attribute information of the file and actual data of the file is being migrated, a content of the access request is stored in a log region of the new file server, and a process according to the content stored in the log region is performed after the file has been migrated.

21. The file migration method according to claim 17, further comprising, after the step of reading out the attribute information, the step of reading the files from the existing file server and storing the files in the new file server according to the attribute information.

22. The file migration method according to claim 21, wherein the new file server accommodates a plurality of file access protocols, and the attribute information of the files is stored according to each of the plurality of file access protocols.

23. A first file server in a computer system including at least a host computer and a second file sever, comprising:

a migration module that reads data and attribute information of at least one file stored in the second file server; and

a second module that operates to store the data and the attribute information of the at least one file read out from the second file server in the first file server without changing contents of the attribute information,

wherein the migration module obtains the attribute information of a directory of the second file server using NFS command and CIFS command, and verifying whether files exist under the directory,

wherein if any files exist, the migration module acquires a NFS attribute information for each of the files under the directory, and acquires a CIFS attribute information for each of the files under the directory;

wherein when the host computer issues a read request to read a first file or file attribute information of the first file during migration process, the migration module determines whether the attribute information of the first file has been migrated to the first file server,

wherein, if the attribute information has not been migrated, the migration module reads the attribute information and data of the first file from the second file server,

if the attribute information has been migrated, the migration module further determines whether data of the first file has been migrated,

wherein in the case data of the first file has not been migrated, the migration module reads the data of the first file from the second file server, and writes the data of the first file into the first file server,

the migration module then reads attribute information and data of the first file from the first file server;

wherein in the case data of the first file has been migrated, the migration module then reads attribute information and data of the first file from the first file server.

24. A first file server in a computer system including at least a host computer and a second file sever, comprising:

a migration module that reads data and attribute information of at least one file stored in the second file server; and

a second module that operates to store the data and the attribute information of the at least one file read out from the second file server in the first file server without changing contents of the attribute information,

wherein the migration module obtains the attribute information of a directory of the second file server using NFS command and CIFS command, and verifying whether files exist under the directory,

wherein if any files exist, the migration module acquires a NFS attribute information for each of the files under the directory, and acquires a CIFS attribute information for each of the files under the directory;

wherein when the host computer issues a request to delete or update a first file during migration process, the migration module determines whether attribute information of the first file has been migrated to the first file server;

wherein, if the attribute information has not been migrated, the migration module reads the file attribute information and data of the first file from the second file server, and writes and updates the attribute information and data of the first file in a log region,

if the attribute information of the file has been migrated, the migration module further determines whether the data of the first file has been migrated,

wherein in the case the data of the first file has not been migrated, the migration module reads data of the first file from the second file server, and writes and updates the data of the first file to the first file server.

25. A file migration method for migrating data in a computer system including at least one computer, and a plurality of file servers each having a storage device, the file migration method comprising:

obtaining by a migration module attribute information of a directory of a first file server using NFS command and CIFS command;

verifying by the migration module whether files exist under the directory,

wherein if any files exist,

obtaining by the migration module a NFS attribute information for files under the directory, and

obtaining by the migration module a CIFS attribute information for files under the directory is obtained;

storing the obtained attribute information in a storage device of a second file server; and

storing in the storage device of the second file server actual data of the file read from the storage device of the first file server according to the attribute information of the file;

wherein when the computer issues a read request to read a first file or file attribute information of the first file during migration process, further comprising;

determining by the migration module whether the attribute information of the first file has been migrated to the second file server,

wherein if the attribute information has not been migrated;

reading by the migration module the attribute information and data of the first file from the first file server;

wherein if the attribute information has been migrated;

determining by the migration module whether data of the first file has been migrated;

wherein in the case data of the first file has not been migrated;

reading by the migration module the data of the first file from the first file server, and

writing the data of the first file into the second file server, and

reading attribute information and data of the first file from the second file server;

wherein in the case data of the first file has been migrated;

reading by the migration module attribute information and data of the first file from the second file server.

26. A file migration method for migrating data in a computer system including at least one computer, and a plurality of file servers each having a storage device, the file migration method comprising:

obtaining by a migration module attribute information of a directory of a first file server using NFS command and CIFS command;

verifying by the migration module whether files exist under the directory,

wherein if any files exist,

obtaining by the migration module a NFS attribute information for files under the directory, and

obtaining by the migration module a CIFS attribute information for files under the directory is obtained;

storing the obtained attribute information in a storage device of a second file server; and

storing in the storage device of the second file server actual data of the file read from the storage device of the first file server according to the attribute information of the file;

wherein when the computer issues a request to delete or update a first file during migration process, further comprising;

determining by the migration module whether attribute information of the first file has been migrated to the second file server;

wherein, if the attribute information has not been migrated;

reading by the migration module the file attribute information and data of the first file from the first file server, and

writing and updating the attribute information and data of the first file in a log region,

wherein if the attribute information of the file has been migrated;

determining by the migration module whether the data of the first file has been migrated,

wherein in the case the data of the first file has not been migrated;

reading by the migration module data of the first file from the first file server, and

writing and updating the data of the first file to the second file server.

27. A file migration method for migrating data in a computer system including at least one host computer, an existing first file server and a new second file server, each of the first file server and the second file server having a storage device, the file migration method comprising:

obtaining by a migration module attribute information of a directory of a first file server using NFS command and CIFS command;

verifying by the migration module whether files exist under the directory,

wherein if any files exist,

obtaining by the migration module a NFS attribute information for files under the directory, and

obtaining by the migration module a CIFS attribute information for files under the directory is obtained;

obtaining actual data of files from the storage device of the first file server and storing in the storage device of the second file server the actual data of the files read from the storage device of the first file server according to the attribute information stored in the storage device of the second file server;

wherein when the host computer issues a read request to read a first file or file attribute information of the first file during migration process, further comprising;

determining by the migration module whether the attribute information of the first file has been migrated to the second file server,

wherein if the attribute information has not been migrated;

reading by the migration module the attribute information and data of the first file from the first file server;

wherein if the attribute information has been migrated;

determining by the migration module whether data of the first file has been migrated;

wherein in the case data of the first file has not been migrated;

reading by the migration module the data of the first file from the first file server, and

writing the data of the first file into the second file server, and

reading attribute information and data of the first file from the second file server;

wherein in the case data of the first file has been migrated;

reading by the migration module attribute information and data of the first file from the second file server.

28. A file migration method for migrating data in a computer system including at least one host computer, an existing first file server and a new second file server, each of the first file server and the second file server having a storage device, the file migration method comprising:

obtaining by a migration module attribute information of a directory of a first file server using NFS command and CIFS command;

verifying by the migration module whether files exist under the directory,

wherein if any files exist,

obtaining by the migration module a NFS attribute information for files under the directory, and

obtaining by the migration module a CIFS attribute information for files under the directory is obtained;

obtaining actual data of files from the storage device of the first file server and storing in the storage device of the second file server the actual data of the files read from the storage device of the first file server according to the attribute information stored in the storage device of the second file server;

wherein when the host computer issues a request to delete or update a first file during migration process, further comprising;

determining by the migration module whether attribute information of the first file has been migrated to the second file server;

wherein, if the attribute information has not been migrated;

reading by the migration module the file attribute information and data of the first file from the first file server, and

writing and updating the attribute information and data of the first file in a log region,

wherein if the attribute information of the file has been migrated;

determining by the migration module whether the data of the first file has been migrated,

wherein in the case the data of the first file has not been migrated;

reading by the migration module data of the first file from the first file server, and

writing and updating the data of the first file to the second file server.

29. A file migration method for migrating date in a computer system including at least one host computer and at least one existing file server, the file migration method comprising the steps of:

disconnecting the existing file server from the computer system;

adding a new file server and connecting the existing file server to the new file server;

obtaining by a migration module attribute information of a directory of the existing server using NFS command and CIFS command;

verifying by the migration module whether files exist under a directory,

wherein if any files exist,

obtaining by the migration module a NFS attribute information for files under the directory, and

obtaining by the migration module a CIFS attribute information for files under the directory is obtained;

reading out a directory tree structure of the existing file server and storing the directory tree structure in the new file server;

reading out all data files in the existing file server and successively writing the data files into the new file server according to the directory tree structure;

wherein when the host computer issues a read request to read a first file or file attribute information of the first file during migration process, further comprising;

determining by the migration module whether the attribute information of the first file has been migrated to the new file server,

wherein if the attribute information has not been migrated;

reading by the migration module the attribute information and data of the first file from the existing file server;

wherein if the attribute information has been migrated;

determining by the migration module whether data of the first file has been migrated;

wherein in the case data of the first file has not been migrated;

reading by the migration module the data of the first file from the first file server, and

writing the data of the first file into the second file server, and

reading attribute information and data of the first file from the new file server;

wherein in the case data of the first file has been migrated;

reading by the migration module attribute information and data of the first file from the new file server.

30. A file migration method for migrating date in a computer system including at least one host computer and at least one existing file server, the file migration method comprising the steps of:

disconnecting the existing file server from the computer system;

adding a new file server and connecting the existing file server to the new file server;

obtaining by a migration module attribute information of a directory of the existing server using NFS command and CIFS command;

verifying by the migration module whether files exist under a directory,

wherein if any files exist,

obtaining by the migration module a NFS attribute information for files under the directory, and

obtaining by the migration module a CIFS attribute information for files under the directory is obtained;

reading out a directory tree structure of the existing file server and storing the directory tree structure in the new file server;

reading out all data files in the existing file server and successively writing the data files into the new file server according to the directory tree structure;

wherein when the host computer issues a request to delete or update a first file during migration process, further comprising;

determining by the migration module whether attribute information of the first file has been migrated to the new server;

wherein, if the attribute information has not been migrated;

reading by the migration module the file attribute information and data of the first file from the existing file server, and

writing and updating the attribute information and data of the first file in a log region,

wherein if the attribute information of the file has been migrated;

determining by the migration module whether the data of the first file has been migrated,

wherein in the case the data of the first file has not been migrated;

reading by the migration module data of the first file from the existing file server, and

writing and updating the data of the first file to the new file server.