Primary stub file retention and secondary retention coordination in a hierarchical storage system
A protected file is retained in secondary storage for a retention period, and a corresponding stub file is retained in primary storage for the retention period. The stub file retains attributes of the file indicating a location of the file data in the secondary storage and indicting that the stub file is to be retained for the retention period. A system administrator may instruct a primary file server that a secondary file server supports retention based protection and it is desired to protect stub files corresponding to protected files that are migrated to the secondary file server. The primary file server may request the secondary file server to return a protection status of the file after migration. This enables automatic policy-based migration to both file level retention (FLR) and non-FLR retention protected secondary storage from diverse applications accessing FLR or non-FLR files in the primary storage.
1. A computer-implemented method of operating a primary file server and a secondary file server in a data network, said method comprising:
the primary file server replacing a specified file in primary storage of the primary file server with a corresponding stub file in the primary storage when data of the specified file are migrated from the primary storage to secondary storage of the secondary file server, the corresponding stub file retaining attributes of the specified file including an indication of a location of the file data in the secondary storage;
wherein the method further includes the secondary file server setting a retention period for the file data in the secondary storage, and the secondary file server retaining the file data in the secondary storage for the retention period; and
wherein the primary file server sets at least one attribute of the corresponding stub file to indicate that the corresponding stub file is to be retained for the retention period, and the primary file server accesses said at least one attribute of the corresponding stub file to reject a request from a client or user to change the specified file prior to expiration of the retention period.
2. The computer-implemented method as claimed in claim 1 , which further includes the primary file server setting an attribute of the corresponding stub file to indicate the retention period of the corresponding stub file.
3. The computer-implemented method as claimed in claim 1 , wherein the retention period of the file data is set by class on the secondary file server, the method includes the primary file server responding to the request from the client or user to change the specified file by obtaining the retention period of the file data from the secondary file server.
4. The computer-implemented method as claimed in claim 1 , which includes a system administrator instructing the primary file server that the secondary file server supports retention based protection and it is desired to protect stub files corresponding to protected files that are migrated to the secondary file server.
5. The computer-implemented method as claimed in claim 1 , which includes the primary file server requesting the secondary file server to return a protection status of the specified file after the data of the specified file have been migrated to the secondary file server, and the secondary file server returning the protection status of the specified file including an indication of whether the specified file is protected or not, and when protected a retention period of the specified file and an indication of whether the retention period can be reduced.
6. The computer-implemented method as claimed in claim 1 , wherein the primary file server includes a connection database, and the corresponding stub file indicates a connection in the connection database for accessing the secondary file server, and the method includes storing in the connection database information specifying a file retention protection technique used by the secondary file server.
7. The computer-implemented method as claimed in claim 1 , which includes the primary file sever protecting the corresponding stub file by detecting that the request from the user is a request to access a specified file that has been replaced with a corresponding stub file, the corresponding stub file indicating a connection to the secondary file server, and the primary file server accessing a connection database to find that the secondary file server supports retention protection for the specified file over the connection indicated by the corresponding stub file.
8. The computer-implemented method as claimed in claim 1 , wherein the corresponding stub file is in a file level retention (FLR) protected file system in the primary storage, and the method includes the primary file server protecting the corresponding stub file by applying FLR functionality.
9. The computer-implemented method as claimed in claim 1 , wherein the specified file is not retention protected when the file data are migrated from the primary file server to the secondary file server and the specified file in the primary storage is replaced with the corresponding stub file in the primary storage, and thereafter the primary file server receives a client or user request to put retention protection upon the specified file, and the primary file server responds by setting the retention period upon the file data in the secondary file server, and by setting the retention period upon the corresponding stub file.
10. The computer-implemented method as claimed in claim 1 , wherein the primary file server responds to a client or user request for retention protection of the specified file by checking whether data of the specified file have been migrated, and upon finding that data of the specified file have been migrated, checking whether retention protection is supported upon the data of the specified file that have been migrated, and upon finding that retention protection is not supported upon the data of the specified file that have been migrated, recalling to the primary file server the data of the specified file that have been migrated, and setting retention protection upon the specified file in the primary file server.
11. A primary file server for use in a data network coupling the primary file server to at least one secondary file server, the primary file server comprising primary storage and being programmed for replacing a specified file in the primary storage with a corresponding stub file in the primary storage when data of the specified file are migrated from the primary storage to secondary storage of the secondary file server, the corresponding stub file storing attributes of the specified file including an indication of a location of the file data in the secondary storage;
wherein the primary file server is programmed for setting at least one attribute of the corresponding stub file to indicate that the corresponding stub file is to be retained for a retention period when the secondary file server supports retention protection of the migrated file data and the secondary file server has been set to retain the migrated file data for the retention period, and the primary file server is programmed for accessing said at least one attribute of the corresponding stub file to reject a request from a client or user to change the specified file prior to expiration of the retention period.
12. The primary file server as claimed in claim 11 , wherein the primary file server is programmed for setting an attribute of the corresponding stub file to indicate the retention period of the corresponding stub file.
13. The primary file server as claimed in claim 11 , wherein the retention period of the specified file is set by class on the secondary file server, and the primary file server is programmed for responding to the request from the client or user to change the specified file by obtaining the retention period of the specified file from the secondary file server.
14. The primary file server as claimed in claim 11 , which is programmed to respond to a request from a system administrator instructing the primary file server that the secondary file server supports retention based protection and it is desired to protect stub files corresponding to protected files that are migrated to the secondary file server.
15. The primary file server as claimed in claim 11 , which further includes a connection database, and the corresponding stub file indicates a connection in the connection database for accessing the secondary file server, and the connection database contains information specifying a file retention protection technique used by the secondary file server.
16. The primary file server as claimed in claim 11 , which is programmed for protecting the corresponding stub file by detecting that the request from the user is a request to access a specified file that has been replaced with a corresponding stub file, the corresponding stub file indicates a connection to the secondary file server, and the primary file server is programmed for accessing a connection database to find that the secondary file server supports retention protection for the specified file over the connection indicated by the corresponding stub file.
17. The primary file server as claimed in claim 11 , wherein the corresponding stub file is in a file level retention (FLR) protected file system in the primary storage, and the primary file server is programmed for protecting the corresponding stub file by applying FLR functionality.
18. The primary file server as claimed in claim 11 , which is programmed to respond to a client or user request for retention protection of the specified file by checking whether data of the specified file have been migrated, and upon finding that data of the specified file have been migrated, checking whether retention protection is supported upon the data of the specified file that have been migrated, and upon finding that retention protection is not supported upon the data of the specified file that have been migrated, recalling to the primary file server the data of the specified file that have been migrated, and setting retention protection upon the specified file in the primary file server.
19. A system comprising a primary file server, a file level retention (FLR) secondary file server, a non-FLR write once read many (WORM) secondary file server, and a data network interconnecting the primary file server to the FLR secondary file server and the WORM secondary file server for migration of file data from the primary file server to the FLR secondary file server and from the primary file server to the WORM secondary file server, wherein the primary file server is programmed for migrating data of FLR files and data of non-FLR files to the FLR secondary file server, and for migrating data of FLR files and data of non-FLR files to the WORM secondary file server,
wherein the primary file server is programmed for replacing a specified file in the primary file server with a corresponding stub file in the primary file server when data of the specified file have been migrated from the primary file server to a selected one of the FLR secondary file server and the WORM secondary file server, the corresponding stub file containing attributes of the specified file including an indication of a location of the data of the specified file in the selected one of the FLR secondary file server and the WORM secondary file server; and
wherein the primary file server is programmed for setting at least one attribute of the corresponding stub file to indicate that the corresponding stub file is to be retained for a retention period of the data of the specified file on the selected one of the FLR secondary file server and the WORM secondary file server, and the primary file server is programmed for accessing said at least one attribute of the corresponding stub file to reject a request from a client or user to change the specified file prior to expiration of the retention period.
20. The system as claimed in claim 19 , wherein the specified file is not retention protected when data of the specified file are migrated from the primary file server to the selected one of the FLR secondary file server and the WORM secondary file server and the specified file in the primary file server is replaced with the corresponding stub file in the primary file server, and the primary file server is programmed for thereafter receiving a client or user request to put retention protection upon the specified file, and the primary file server is programmed to respond to the client or user request to put retention protection upon the specified file by setting the retention period upon the data of the specified file in the selected one of the FIR secondary file server and the WORM secondary file server, and by setting the retention period upon the corresponding stub file.