MANAGING REDUNDANT IMMUTABLE FILES USING DEDUPLICATION IN STORAGE CLOUDS

• US 20150039570A1
• Filed: 10/17/2014
• Published: 02/05/2015
• Est. Priority Date: 12/02/2011
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: CHHAUNKER, Gaurav, JAIN, Bhushan P., PATIL, Sandeep R., RAMANATHAN, Sri, TREVATHAN, Matthew B.
• Granted Patent: US 9,158,783 B2
• Time in Patent Office: Days
• US Class Current: 707/692
• CPC Class Codes: G06F 16/00 Information retrieval; Database structures therefor; File system structures therefor
• CPC Class Codes: G06F 16/13 File access structures, e.g. distributed indices arrangements of input from, or output to, record carriers G06F3/06
• CPC Class Codes: G06F 16/162 Delete operations erasing in storage systems G06F3/0652
• CPC Class Codes: G06F 16/174 Redundancy elimination performed by the file system management of the data involved in backup or backup restore using de-duplication of the data G06F11/14
• CPC Class Codes: G06F 16/1748 De-duplication implemented within the file system, e.g. based on file segments de-duplication techniques in storage systems for the management of data blocks G06F3/0641
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 16/2379 Updates performed during online database operations; commit processing
• CPC Class Codes: G06F 7/00 Methods or arrangements for processing data by operating upon the order or content of the data handled logic circuits H03K19/00
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]

Abstract

A method includes receiving a request to save a first file as immutable. The method also includes searching for a second file that is saved and is redundant to the first file. The method further includes determining the second file is one of mutable and immutable. When the second file is mutable, the method includes saving the first file as a master copy, and replacing the second file with a soft link pointing to the master copy. When the second file is immutable, the method includes determining which of the first and second files has a later expiration date and an earlier expiration date, saving the one of the first and second files with the later expiration date as a master copy, and replacing the one of the first and second files with the earlier expiration date with a soft link pointing to the master copy.

Claims

1. A system for file deduplication implemented in hardware and comprising a computer infrastructure comprising at least one computer device operable to:

receive, by the at least one computer device, a request to save a first file as immutable;

determine, by the at least one computer device, a plurality of second files that are redundant to the first file;

determine, by the at least one computer device, each one of the plurality of second files is immutable;

identify, by the at least one computer device, a file having a latest expiration date from a group comprising the first file and the plurality of second files;

save, by the at least one computer device, the file having the latest expiration date as a master copy; and

replace, by the at least one computer device, each file in the group, except for the file having the latest expiration date, with a respective data structure pointing to the master copy.

2. The system of claim 1, wherein the respective data structure comprises an immutability expiration date.

3. The system of claim 1, wherein the respective data structure comprises a soft link comprising an immutability expiration date.

4. The system of claim 1, wherein the request to save the first file comprises a request or instruction to save the first file in a shared storage.

5. The system of claim 4, wherein:

the request to save the first file is received from a local computing device;

the shared storage is in a cloud environment remote from the local computing device; and

the master copy is saved in the shared storage.

6. The system of claim 1, wherein the determining the plurality of second files that are redundant to the first file comprises comparing a hash value of the first file to hash values of other saved files.

7. The system of claim 1, wherein the at least one computer device is further operable to one of delete the master copy and mark the master copy as mutable upon reaching the latest expiration date.

8. The system of claim 7, wherein the at least one computer device is further operable to:

determine a soft link having a new latest expiration date from a plurality of soft links pointing to the master copy; and

promote the soft link having the new latest expiration date as a new master copy; and

update the plurality of soft links, other than the soft link having the new latest expiration date, to point to the new master copy.

9. The system of claim 1, wherein the at least one computer device comprises:

one or more computer processors;

a computer readable hardware storage device; and

program instructions stored on the computer readable hardware storage device for execution by the one or more computer processors.

10. A computer program product comprising a computer readable hardware storage device having readable program code stored on the computer readable hardware storage device, the program code comprising:

program code to receive a request to save a first file as immutable in a shared storage, wherein the request is received from a local computing device remote from the shared storage;

program code to identify at least one second file that is saved in the shared storage and is redundant to the first file;

program code to determine the at least one second file is one of mutable and immutable;

program code to, when the at least one second file is mutable, save the first file as a master copy, and replace each of the at least one second file with a respective soft link pointing to the master copy; and

program code to, when the at least one second file is immutable;

identify a file having a latest expiration date from a group comprising the first file and the at least one second file;

save the file having the latest expiration date as a master copy; and

replace each file in the group, except for the file having the latest expiration date, with a respective data structure pointing to the master copy.