Managing files using layout storage objects

• US 20090112921A1
• Filed: 10/31/2007
• Published: 04/30/2009
• Est. Priority Date: 10/31/2007
• Status: Abandoned Application

• Current Assignee: EMC Corporation (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Fridella, Stephen, Dimitrov, Rossen, Oliveira, Fernando, Eaton, Patrick
• Application Number:
  US11/981,815
• Publication Number:
  US 20090112921A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/178 Techniques for file synchronisation in file systems

Abstract

Managing a plurality of files includes providing at least one server having a table with plurality of file identifiers, each of the file identifiers including a pointer to a metadata file object containing a layout storage object that indicates storage parameters for corresponding files and includes accessing a particular one of the files by obtaining information from the at least one server to access the layout storage object corresponding to the particular file to determine synchronous and asynchronous mirrors for the file. Each layout storage object may be provided as a tree and leaves of the tree may map logical addresses of a corresponding file to data storage locations. At least one internal node of the tree may indicate that at least one leaf node thereof is a mirror of an other leaf node thereof.

Claims

1. A method of managing a plurality of files, comprising:

providing at least one server having a table with plurality of file identifiers, each of the file identifiers including a pointer to a metadata file object containing a layout storage object that indicates storage parameters for corresponding files; and

accessing a particular one of the files by obtaining information from the at least one server to access the layout storage object corresponding to the particular file to determine synchronous and asynchronous mirrors for the file.

2. A method, according to claim 1, wherein each layout storage object is provided as a tree and wherein leaves of the tree map logical addresses of a corresponding file to data storage locations.

3. A method, according to claim 2, wherein at least one internal node of the tree indicates that at least one leaf node thereof is a mirror of an other leaf node thereof.

4. A method, according to claim 3,wherein, in response to a data write and an internal node indicating that a first leaf node thereof is an asynchronous mirror of a second leaf node thereof, writing the data to the first leaf node and providing an update message to the at least one server.

5. A method, according to claim 4, further comprising:

the at least one server placing information on a queue corresponding to the message and servicing the queue to write the data to the second leaf node.

6. A method, according to claim 3, wherein, in response to a data write and an internal node indicating that a first leaf node thereof is a synchronous mirror of a second leaf node thereof, writing the data to the first leaf node and to the second leaf node.

7. A method, according to claim 1, wherein, in response to accessing data being unsuccessful, accessing a mirror thereof.

8. A method, according to claim 1, wherein the layout storage object includes pointers to data file objects that map a logical address space for a corresponding file to data storage space corresponding to physical data storage.

9. A method, according to claim 8, wherein each data file object has a state indicating that the data file object is one of:

current, an out-of-date mirror of another data object, immutable, and invalid.

10. A method, according to claim 9, wherein, in response to an attempt to write to a data file object that is immutable, new storage space is allocated and data is written to the new storage space.

11. A method, according to claim 9, wherein, in response to an attempt to read a data file object that is invalid, zeros are returned.

12. Computer software, provided in a computer-readable medium, that manages a plurality of files, the software comprising:

executable code provided in at least one server that manages a table with plurality of file identifiers, each of the file identifiers including a pointer to a metadata file object containing a layout storage object that indicates storage parameters for corresponding files; and

executable code that accesses a particular one of the files by obtaining information from the at least one server to access the layout storage object corresponding to the particular file to determine synchronous and asynchronous mirrors for the file.

13. Computer software, according to claim 12, wherein each layout storage object is provided as a tree and wherein leaves of the tree map logical addresses of a corresponding file to data storage locations.

14. Computer software, according to claim 13, wherein at least one internal node of the tree indicates that at least one leaf node thereof is a mirror of an other leaf node thereof.

15. Computer software, according to claim 14, wherein, in response to a data write and an internal node indicating that a first leaf node thereof is an asynchronous mirror of a second leaf node thereof, executable code causes the data to be written to the first leaf node and an update message to be provided to the at least one server.

16. Computer software, according to claim 15, wherein executable code at the at least one server places information on a queue corresponding to the message and services the queue to write the data to the second leaf node.

17. Computer software, according to claim 14, wherein, in response to a data write and an internal node indicating that a first leaf node thereof is a synchronous mirror of a second leaf node thereof, executable code causes the data to be written to the first leaf node and to the second leaf node.

18. Computer software, according to claim 12, further comprising:

executable code that, in response to accessing data being unsuccessful, accesses a mirror thereof.

19. Computer software, according to claim 12, wherein the layout storage object includes pointers to data file objects that map a logical address space for a corresponding file to data storage space corresponding to physical data storage.

20. Computer software, according to claim 19, wherein each data file object has a state indicating that the data file object is one of:

current, an out-of-date mirror of another data object, immutable, and invalid.

21. Computer software, according to claim 20, further comprising:

executable code that allocates new storage space and writes data to the new storage space in response to an attempt to write to a data file object that is immutable.

22. Computer software, according to claim 20, further comprising:

executable code that causes zeros to be returned in response to an attempt to read a data file object that is invalid.

23. A method of managing a plurality of files, comprising:

providing at least one server having a plurality of file identifiers, each of the file identifiers including a pointer to a metadata file object containing a layout storage object that indicates storage parameters for corresponding files; and

accessing a particular one of the files by obtaining information from the at least one server to access the layout storage object corresponding to the particular file to determine how data for the file is stored and retrieved.

24. A data storage system, comprising:

a plurality of servers, wherein at least one server has a table with plurality of file identifiers, each of the file identifiers including a pointer to a metadata file object containing a layout storage object that indicates storage parameters for corresponding files; and

a plurality of clients that access a particular one of the files by obtaining information from the at least one server to access the layout storage object corresponding to the particular file to determine synchronous and asynchronous mirrors for the file.

25. A data storage system, comprising:

a plurality of servers, wherein at least one server has a plurality of file identifiers, each of the file identifiers including a pointer to a metadata file object containing a layout storage object that indicates storage parameters for corresponding files; and

a plurality of clients that access a particular one of the files by obtaining information from the at least one server to access the layout storage object corresponding to the particular file to determine how data for the file is stored and retrieved.