Non-disruptive file migration

1. In a switched file system having a file switch in communication with a plurality of file servers including at least a source server and a destination server, where the source server manages a source native volume, a method for non-disruptive migration of the native volume from the source server to the destination server, the method comprising:

converting, by the file switch, the source native volume to a native with metadata volume using a local file system managed by the file switch;

converting, by the file switch, the native with metadata volume to a mirrored native with metadata volume, wherein the converting takes place in both the source server and the destination server, the destination server including a mirror copy of the native with metadata volume;

removing, by the file switch, the source server from the mirrored native with metadata volume, wherein the removing includes physically deleting and disconnecting the source server from the mirrored native with metadata volume; and

converting, by the file switch, the mirror copy of the native with metadata volume on the destination server to a destination native volume on the destination server.

2. A method according to claim 1 , wherein converting the source native volume to the native with metadata volume comprises:

for each source directory in the source native volume, creating a corresponding local directory in the local file system including metadata associated with the source directory copied from the source native volume; and

for each source file in the source native volume, creating a corresponding local sparse file in the local file system including file attributes copied from the source native volume but excluding the file contents associated with the source file.

3. A method according to claim 2 , wherein the metadata associated with the source directory copied from the source native volume comprises directory security descriptors.

4. A method according to claim 2 , wherein creating a local directory for a source directory comprises:

opening the source directory in the source native volume;

placing a lock on the source directory; and

creating the local directory and its metadata.

5. A method according to claim 1 , wherein converting the native with metadata volume to the mirrored native with metadata volume comprises:

for each local directory, creating a corresponding destination directory in the destination server and maintaining a mapping of the local directory to a source directory pathname for the corresponding source directory in the source server and to a destination directory pathname for the corresponding destination directory in the destination server;

for each local file, creating a corresponding destination file in the destination server including file data copied from the source native volume and maintaining a mapping of the local file to a source file pathname for the corresponding source file in the source server and to a destination file pathname for the corresponding destination file in the destination server.

6. A method according to claim 5 , wherein each mapping includes an indicator of the number of servers associated with the mirrored native with metadata volume.

7. A method according to claim 5 , wherein removing the source server from the mirrored native with metadata volume comprises:

disabling usage of the source destination pathnames and the source file pathnames.

8. A method according to claim 5 , wherein converting the mirror copy of the native with metadata volume on the destination server to a destination native volume comprises:

replicating state information for the destination directories and the destination files from the source native volume;

disabling usage of the local directories and local files; and

advertising the destination directories and destination files as a native volume.

9. A method according to claim 8 , wherein converting the mirror copy of the native with metadata volume on the destination server to a destination native volume further comprises:

deleting unneeded metadata associated with the mirror copy of the native with metadata volume from the destination server.

10. A file switch for non-disruptive file migration in a switched file system having a plurality of file servers including at least a source server and a destination server, where the source server manages a source native volume, the file switch comprising:

a network interface for communication with the file servers;

a processor coupled to the network interface; and

a memory coupled to the processor, wherein the processor is configured to execute programmed instructions stored in the memory comprising:

converting the source native volume to a native with metadata volume using a local file system managed by the file switch;

converting , the native with metadata volume to a mirrored native with metadata volume, wherein the converting takes place in both the source server and the destination server, the destination server including a mirror copy of the native with metadata volume;

removing the source server from the mirrored native with metadata volume, wherein the removing includes physically deleting and disconnecting the source server from the mirrored native with metadata volume; and

converting the mirror copy of the native with metadata volume on the destination server to a destination native volume on the destination server.

11. A file switch according to claim 10 , wherein the processor is further configured to execute program instructions stored in the memory further comprising converting the source native volume to the native with metadata volume by:

creating, for each source directory in the source native volume, a corresponding local directory in the local file system including metadata associated with the source directory copied from the source native volume; and

creating, for each source file in the source native volume, a corresponding local sparse file in the local file system including file attributes copied from the source native volume but excluding the file contents associated with the source file.

12. A file switch according to claim 11 , wherein the metadata associated with the source directory copied from the source native volume comprises directory security descriptors.

13. A file switch according to claim 11 , wherein the processor is further configured to execute program instructions stored in the memory further comprising creating a local directory for a source directory by opening the source directory in the source native volume; placing a lock on the source directory; and creating the local directory and its metadata.

14. A file switch according to claim 10 , wherein the processor is further configured to execute program instructions stored in the memory further comprising converting the native with metadata volume to the mirrored native with metadata volume by:

creating, for each local directory, a corresponding destination directory in the destination server and maintaining a mapping of the local directory to a source directory pathname for the corresponding source directory in the source server and to a destination directory pathname for the corresponding destination directory in the destination server; and

creating, for each local file, a corresponding destination file in the destination server including file data copied from the source native volume and maintaining a mapping of the local file to a source file pathname for the corresponding source file in the source server and to a destination file pathname for the corresponding destination file in the destination server.

15. A file switch according to claim 14 , wherein each mapping includes an indicator of the number of servers associated with the mirrored native with metadata volume.

16. A file switch according to claim 14 , wherein the processor is further configured to execute program instructions stored in the memory further comprising removing the source server from the mirrored native with metadata volume by disabling usage of the source destination pathnames and the source file pathnames.

17. A file switch according to claim 14 , wherein the processor is further configured to execute program instructions stored in the memory further comprising:

converting the mirror copy of the native with metadata volume on the destination server to a destination native volume by replicating state information for the destination directories and the destination files from the source native volume;

disabling usage of the local directories and local files; and

advertising the destination directories and destination files as a native volume.

18. A file switch according to claim 17 , wherein the processor is further configured to execute program instructions stored in the memory further comprising converting the mirror copy of the native with metadata volume on the destination server to a destination native volume further by deleting unneeded metadata associated with the mirror copy of the native with metadata volume from the destination server.

19. A non-transitory computer readable medium having stored thereon instructions for non-disruptive file migration in a switched file system having a plurality of file servers, including at least a source server and a destination server, where the source server manages a source native volume, comprising machine executable code which when executed by at least one processor, causes the processor to perform steps comprising:

converting the source native volume to a native with metadata volume using a local file system;

converting the native with metadata volume to a mirrored native with metadata volume, wherein the converting takes place in both the source server and the destination server, the destination server including a mirror copy of the native with metadata volume;

removing the source server from the mirrored native with metadata volume, wherein the removing includes physically deleting and disconnecting the source server from the mirrored native with metadata volume; and

converting the mirror copy of the native with metadata volume on the destination server to a destination native volume on the destination server.

20. A medium according to claim 19 , further having stored thereon instructions that when executed by the at least one processor causes the at least one processor to perform steps further comprising:

creating, for each source directory in the source native volume, a corresponding local directory in the local file system including metadata associated with the source directory copied from the source native volume; and

creating, for each source file in the source native volume, a corresponding local sparse file in the local file system including file attributes copied from the source native volume but excluding the file contents associated with the source file.

21. A medium according to claim 20 , wherein the metadata associated with the source directory copied from the source native volume comprises directory security descriptors.

22. A medium according to claim 20 , further having stored thereon instructions that when executed by the at least one processor causes the at least one processor to perform steps further comprising creating a local directory for a source directory by opening the source directory in the source native volume; placing a lock on the source directory; and creating the local directory and its metadata.

23. A medium according to claim 19 , further having stored thereon instructions that when executed by the at least one processor causes the at least one processor to perform steps further comprising converting the native with metadata volume to the mirrored native with metadata volume by:

creating, for each local directory, a corresponding destination directory in the destination server and maintaining a mapping of the local directory to a source directory pathname for the corresponding source directory in the source server and to a destination directory pathname for the corresponding destination directory in the destination server; and

creating, for each local file, a corresponding destination file in the destination server including file data copied from the source native volume and maintaining a mapping of the local file to a source file pathname for the corresponding source file in the source server and to a destination file pathname for the corresponding destination file in the destination server.

24. A medium according to claim 23 , wherein each mapping includes an indicator of the number of servers associated with the mirrored native with metadata volume.

25. A medium according to claim 23 further having stored thereon instructions that when executed by the at least one processor causes the at least one processor to perform steps further comprising removing the source server from the mirrored native with metadata volume by disabling usage of the source destination pathnames and the source file pathnames.

26. A medium according to claim 23 , further having stored thereon instructions that when executed by the at least one processor causes the at least one processor to perform steps further comprising:

converting the mirror copy of the native with metadata volume on the destination server to a destination native volume by replicating state information for the destination directories and the destination files from the source native volume;

disabling usage of the local directories and local files; and

advertising the destination directories and destination files as a native volume.

27. A medium according to claim 26 , further having stored thereon instructions that when executed by the at least one processor causes the at least one processor to perform steps further comprising converting the mirror copy of the native with metadata volume on the destination server to a destination native volume further by deleting unneeded metadata associated with the mirror copy of the native with metadata volume from the destination server.