LOCAL FILE SERVER TRANSFERRING FILE TO REMOTE FILE SERVER VIA COMMUNICATION NETWORK AND STORAGE SYSTEM COMPRISING THOSE FILE SERVERS

• US 20120016838A1
• Filed: 05/27/2010
• Published: 01/19/2012
• Est. Priority Date: 05/27/2010
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kanie, Homare, Saika, Nobuyuki, Arai, Hitoshi
• Granted Patent: US 8,832,025 B2
• Time in Patent Office: Days
• US Class Current: 707/610
• CPC Class Codes: G06F 16/113 Details of archiving lifecycle management in storage systems G06F3/0649; backup systems G06F11/1446
• CPC Class Codes: G06F 16/178 Techniques for file synchronisation in file systems
• CPC Class Codes: G06F 16/1844 Management specifically adapted to replicated file systems
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0649 Lifecycle management
• CPC Class Codes: G06F 3/0683 Plurality of storage devices
• CPC Class Codes: G06F 3/0685 Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes

Abstract

A remote file server managing a remote storage device and a local file server managing a local storage device are coupled to a communication network (e.g. the Internet). The local file server (A) replicates a file in the local storage device to the remote file server and, (B) if a first condition is satisfied, manages the replicated file which is the file from which the data is replicated as a migration target file. The local file server, even if the (B) is completed, does not delete the migration target file from the local storage device and, if the second condition is satisfied, deletes the migration target file from the local storage device.

Claims

1. A file server which is a local file server that is coupled to a communication network to which is coupled to a remote file server managing a remote storage device and that manages a local storage device, the file server comprising:

a first communication interface device which is coupled to the communication network;

a second communication interface device which is coupled to a user terminal for sending an access request that is either a read request or a write request specifying a file, and which receives the access request from the user terminal; and

a processor which is coupled to the first and second interface devices, wherein the processor;

(A) replicates a file in the local storage device to the remote file server;

(B) manages the replicated file, which is the file from which data is replicated, as a migration target file in a case where a first condition is satisfied; and

(C) does not delete the migration target file from the local storage device even if the (B) is completed, and deletes the migration target file from the local storage device when a second condition is satisfied.

2. A file server according to claim 1, wherein the communication network is the Internet,

the second communication interface device is coupled to multiple user terminals, and

the second condition is that the migration target file is referred to, and then not referred to by any of the user terminals.

3. A file server according to claim 2, wherein each user terminal sends an open request before the read request, and sends a close request after the read request,

the processor:

(E) updates a count value of the migration target file in accordance with a first rule each time receiving the open request; and

(F) updates a count value of the migration target file in accordance with a second rule each time receiving the close request,

the second condition is that, after the updating of the count value of the migration target file is started, the count value becomes a specified value, and

the specified value is equivalent to the fact that the file is not referred to by any of the user terminals.

4. A file server according to claim 3, wherein the first condition is that the free capacity of the local storage device is below a specified threshold.

5. A file server according to claim 4, wherein the processor:

(H) manages the replicated file as a synchronization target file upon receiving a write request with respect to the replicated file; and

(I) transfers the synchronization target file to the remote file server so that the replicated file managed by the remote file server matches the synchronization target file, and

the processor makes a determination as to whether or not the first condition is satisfied subsequent to the (I).

6. A file server according to claim 5, wherein the processor:

(K) upon receiving a write request with respect to a stub of the migration target file that has been deleted from the local storage device, acquires, from the remote file server, a file managed by the remote file server which is the link destination identified from this stub;

(L) stores the acquired file in the local storage device; and

(M) updates the acquired file in accordance with the write request received in the (K), and

the processor releases the stub when performing the (K).

7. A file server according to claim 6, wherein the local storage device stores multiple replicated files, and one or more non-replication-target files which is one or more files other than the multiple replicated files, and

the processor:

(O) extracts one or more common characteristics of the multiple replicated files based on metadata of the multiple replicated files;

(P) selects, from among the one or more non-replication-target files, a non-replication-target file that corresponds to the metadata matching the one or more common characteristics; and

(Q) migrates the selected non-replication-target file to the remote file server.

8. A file server according to claim 1, wherein the first condition is that the free capacity of the local storage device is below a specified threshold.

9. A file server according to claim 8, wherein the processor:

(H) manages the replicated file as a synchronization target file upon receiving a write request with respect to the replicated file; and

(I) transfers the synchronization target file to the remote file server so that the replicated file managed by the remote file server matches the synchronization target file, and

the processor makes a determination as to whether or not the first condition is satisfied subsequent to the (I).

10. A file server according to claim 1, wherein the processor:

(K) upon receiving a write request with respect to a stub of the migration target file that has been deleted from the local storage device, acquires, from the remote file server, a file managed by the remote file server which is the link destination identified from this stub;

(L) stores the acquired file in the local storage device; and

(M) updates the acquired file in accordance with the write request received in the (K), and

the processor releases the stub when performing the (K).

11. A file server according to claim 1, wherein the local storage device stores multiple replicated files, and one or more non-replication-target files which is one or more files other than the multiple replicated files, and

the processor:

(O) extracts one or more common characteristics of the multiple replicated files based on metadata of the multiple replicated files;

(P) selects, from among the one or more non-replication-target files, a non-replication-target file that corresponds to the metadata matching the one or more common characteristics; and

(Q) migrates the selected non-replication-target file to the remote file server.

12. A file server according to claim 11, wherein the processor executes the (P) in a case where the ratio of the total capacity of the one or more non-replication-target files to the capacity of the local storage device is a certain value or larger.

13. A file server according to claim 12, wherein, in the (P), one or more non-replication-target files are selected so that the ratio falls below the certain value.

14. A storage system comprising:

a remote file server which manages a remote storage device; and

a local file server which manages a local storage device and is coupled to the remote file server via a communication network,

wherein;

(A) the local file server transfers a file in the local storage device to the remote file server via the communication network, and the remote file server stores this file in the remote storage device, thereby replicating data from this file;

(B) in a case where a first condition is satisfied, the local file server manages, as a migration-target file, the replicated file in the local storage device, which is the file from which the data is replicated; and

(C) the local file server does not delete the migration target file from the local storage device even if the (B) is completed, and deletes the migration target file from the local storage device when a second condition is satisfied.

15. A computer program that causes a local file server that is coupled to a communication network to which is connected a remote file server managing a remote storage device and that manages a local storage device, to execute the following (A) through (C):

(A) replicates a file in the local storage device to the remote file server;

(B) manages the replicated file, which is the file from which data is replicated, as a migration target file in a case where a first condition is satisfied; and

(C) does not delete the migration target file from the local storage device even if the (B) is completed, and deletes the migration target file from the local storage device when a second condition is satisfied.