Atomically managing data objects and assigned attributes

• US 10,733,161 B1
• Filed: 12/30/2015
• Issued: 08/04/2020
• Est. Priority Date: 12/30/2015
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Davenport, William C., Tummala, Himabindu, Vankamamidi, Vamsi
• Primary Examiner(s): Singh, Amresh
• Application Number:
  US14/984,224
• Time in Patent Office: 1,679 Days
• Field of Search: None
• CPC Class Codes: G06F 16/213 with details for schema evolution support
• CPC Class Codes: G06F 16/219 Managing data history or versioning querying versioned data G06F16/2474; querying temporal data G06F16/2477
• CPC Class Codes: G06F 16/22 Indexing; Data structures therefor; Storage structures
• CPC Class Codes: G06F 16/2358 Change logging, detection, and notification replication G06F16/27
• CPC Class Codes: G06F 16/24573 using data annotations, e.g. user-defined metadata

Abstract

A technique for managing data storage places a data object in a first logical extent within a logical address space of a storage system and places a set of attributes assigned to that data object in a second logical extent within the same logical address space of the storage system. In response to a request to generate a second version of the data object, such as a snap, clone, or replica, for example, the first and second logical extents are duplicated atomically, thereby preserving a second version of the attributes along with the second version of the data object.

Claims

1. A method of managing data storage, the method comprising:

placing a data object in a first logical extent within a logical address space of a storage system, the first logical extent being a contiguous range of logical addresses that has a starting offset and a length;

placing a set of attributes of the data object in a second logical extent within the logical address space of the storage system, the set of attributes including information applied to the data object by one or more software constructs that have access to the data object, the logical address space providing a contiguous range of logical addresses within which the first logical extent and the second logical extent are disposed at respective logical addresses;

storing data of the first and second logical extents in a set of persistent storage devices; and

in response to a request to generate a second version of the data object, atomically duplicating the first logical extent together with the second logical extent, thereby preserving a second version of the attributes of the data object together with the second version of the data object,

wherein the data object is associated with an inode that provides information about the data object, and wherein atomically duplicating the first logical extent together with the second logical extent includes creating a snapshot, the snapshot providing a unique copy of the inode but not a unique copy of the data of the first logical extent nor a unique copy of the second logical extent, the snapshot providing a point-in-time version of the data object and of the set of attributes and remaining stable even as the data object and the set of attributes change over time.

2. The method of claim 1, wherein the data object is one of (i) a LUN (Logical UNit), a file system, and a virtual machine volume.

3. The method of claim 2, further comprising placing the inode in a third logical extent within the logical address space of the storage system, the inode including a set of pointers to locations of the first logical extent and the second logical extent within the logical address space of the storage system.

4. The method of claim 3, wherein the set of attributes includes multiple attributes, and wherein the inode includes a respective pointer to each of the multiple attributes.

5. The method of claim 4, wherein the first logical extent includes a first region that contains the data object and a second region that contains additional space, and wherein the second logical extent is disposed within the additional space contained in the second region of the first logical extent.

6. The method of claim 3, further comprising:

in response to a request to generate a third version of the data object, atomically duplicating both the first logical extent and the second logical extent, thereby preserving the attributes of the data object with the third version of the data object,

wherein generating the third version of the data object includes generating a unique copy of the inode, generating a unique copy of the data of the first logical extent, and generating a unique copy of the data of the second logical extent.

7. The method of claim 3, further comprising:

in response to a request to generate a fourth version of the data object, atomically duplicating both the first logical extent and the second logical extent, thereby preserving the attributes of the data object with the fourth version of the data object,

wherein the set of persistent storage devices are disposed within a first storage system, and wherein generating the fourth version of the data object includes copying the data of the first logical extent and the data of the second logical extent to a second storage system.

8. A computer program product including a set of non-transitory, computer-readable media having instructions which, when executed by control circuitry, cause the control circuitry to perform a method of managing data storage, the method comprising:

placing a data object in a first logical extent within a logical address space of a storage system, the first logical extent being a contiguous range of logical addresses that has a starting offset and a length;

placing a set of attributes of the data object in a second logical extent within the first logical extent, the set of attributes including information applied to the data object by one or more software constructs that have access to the data object, the logical address space providing a contiguous range of logical addresses within which the first logical extent and the second logical extent are disposed at respective logical addresses;

storing data of the first logical extent, which includes data of the second logical extent, in a set of persistent storage devices; and

in response to a request to generate a second version of the data object, duplicating the first logical extent, thereby preserving a second version of the attributes of the data object together with the second version of the data object,

wherein the method further comprises placing an inode in a third logical extent within the logical address space of the storage system, the inode providing information about the data object and including a set of pointers to locations of the first logical extent and the second logical extent within the logical address space of the storage system, and

wherein duplicating the first logical extent includes creating a snapshot, the snapshot providing a unique copy of the inode but not a unique copy of the data of the first logical extent, the snapshot providing a point-in-time version of the data object and of the set of attributes and remaining stable even as the data object and the set of attributes change over time.

9. The computer program product of claim 8, wherein the data object is one of (i) a LUN (Logical UNit), a file system, and a virtual machine volume.

10. The computer program product of claim 8, wherein the set of attributes includes multiple attributes, and wherein the inode includes a respective pointer to each of the multiple attributes.

11. The computer program product of claim 8, wherein the method further comprises:

in response to a request to generate a third version of the data object, duplicating the first logical extent, thereby preserving the attributes of the data object with the third version of the data object,

wherein duplicating the first logical extent includes generating a unique copy of the inode and generating a unique copy of the data of the first logical extent.

12. The computer program product of claim 8, wherein the method further comprises:

in response to a request to generate a fourth version of the data object, duplicating the first logical extent, thereby preserving the attributes of the data object with the fourth version of the data object,

wherein duplicating the first logical extent includes copying the data of the first logical extent to a second storage system.

13. A data storage system, comprising:

a set of persistent storage devices; and

control circuitry, coupled to the set of persistent storage devices, the control circuitry constructed and arranged to;

place a data object in a first logical extent within a logical address space of a storage system, the first logical extent being a contiguous range of logical addresses that has a starting offset and a length;

place a set of attributes of the data object in a second logical extent within first logical extent, the set of attributes including information applied to the data object by one or more software constructs that have access to the data object, the logical address space providing a contiguous range of logical addresses within which the first logical extent and the second logical extent are disposed at respective logical addresses;

store data of the first logical extent, which includes data of the second logical extent, in a set of persistent storage devices; and

in response to a request to generate a second version of the data object, duplicate the first logical extent, thereby preserving a second version of the attributes of the data object together with the second version of the data object,

wherein the control circuitry is further constructed and arranged to place an inode in a third logical extent within the logical address space of the storage system, the inode providing information about the data object and including a set of pointers to locations of the first logical extent and the second logical extent within the logical address space of the storage system, and

wherein, the control circuitry, constructed and arranged to generate the second version of the data object, is further constructed and arranged to generate a snapshot, the snapshot providing a unique copy of the inode but not a unique copy of the data of the first logical extent, the snapshot providing a point-in-time version of the data object and of the set of attributes and remaining stable even as the data object and the set of attributes change over time.

14. The data storage system of claim 13, wherein the data object is one of (i) a LUN (Logical UNit), a file system, and a virtual machine volume.

15. The data storage system of claim 13, wherein the control circuitry is further constructed and arranged to:

in response to a request to generate another version of the data object, duplicate the first logical extent, thereby preserving the attributes of the data object with the other version of the data object,

wherein duplicating the first logical extent includes copying the data of the first logical extent to a second data storage system.