REDUCING THE SIZE OF FAULT DOMAINS

• US 20200133808A1
• Filed: 10/30/2018
• Published: 04/30/2020
• Est. Priority Date: 10/30/2018
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Patel, Dixit, Davenport, William
• Granted Patent: US 10,929,255 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1453 using de-duplication of the data
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 12/109 for multiple virtual address spaces, e.g. segmentation G06F12/1036 takes precedence
• CPC Class Codes: G06F 2201/805 Real-time
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency ensuring consistency in mirrored systems G06F11/2064
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc
• CPC Class Codes: G06F 2212/657 Virtual address space management
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A separate family space is provisioned as a separate fault domain for each production device in a storage system. The space provisioned for each family has contiguous logical block addresses that do not overlap with the address space of any other family. Snaps and clones in a first family space are used for fault recovery without interrupting IOs to a second family space. If the first family space points to the same virtual block as other families as a result of deduplication then the virtual block is un-deduped. For example, another instance of the virtual block may be created and pointers updated such that only the first family space points to one of the virtual block instances.

Claims

1. A method comprising:

in a storage array comprising a plurality of interconnected computing nodes and a plurality of groups of non-volatile data storage drives, each group of data storage drives connected with one of the computing nodes;

presenting a plurality of production devices for storage of host application data;

provisioning, in a virtual storage space, a separate family space as a separate fault domain for each of the production devices, including a first family space for a first production device and a second family space for a second production device;

storing a first snap of the first production device in the first family space;

storing a second snap of the second production device in the second family space; and

recovering from a fault associated with the first production device by accessing the first snap without interrupting input-output commands to the second production device.

2. The method of claim 1 wherein provisioning the separate family space for each of the production devices comprises provisioning contiguous logical block addresses for the first family.

3. The method of claim 2 comprising provisioning contiguous logical block addresses for the second family such that the logical block addresses of the first family and the second family do not overlap.

4. The method of claim 1 comprising storing a first clone of the first production device in the first family space.

5. The method of claim 4 comprising storing a second clone of the second production device in the second family space.

6. The method of claim 1 comprising recognizing that a first virtual block associated with the first snap is associated with a first pointer structure from the first family space and a second pointer structure from the second family space.

7. The method of claim 6 comprising creating a second virtual block that is a copy of the first virtual block.

8. The method of claim 7 comprising modifying the first pointer structure to associate the first snap with the second virtual block.

9. The method of claim 7 comprising modifying the second pointer structure to associate the second snap with the second virtual block.

10. An apparatus comprising:

a plurality of interconnected computing nodes that present a plurality of production devices for storage of host application data;

a plurality of groups of non-volatile data storage drives, each group of data storage drives connected with one of the computing nodes, the data storage drives storing the host application data; and

program code that;

provisions, in a virtual storage space, a separate family space as a separate fault domain for each of the production devices, including a first family space for a first production device and a second family space for a second production device;

stores a first snap of the first production device in the first family space;

stores a second snap of the second production device in the second family space; and

recovers from a fault associated with the first production device by accessing the first snap without interrupting input-output commands to the second production device.

11. The apparatus of claim 10 wherein the program code provisions contiguous logical block addresses for the first family.

12. The apparatus of claim 11 wherein the program code provisions contiguous logical block addresses for the second family such that the logical block addresses of the first family and the second family do not overlap.

13. The apparatus of claim 10 wherein the program code stores a first clone of the first production device in the first family space.

14. The apparatus of claim 13 wherein the program code stores a second clone of the second production device in the second family space.

15. The apparatus of claim 10 wherein the program code recognizes that a first virtual block associated with the first snap is associated with a first pointer structure from the first family space and a second pointer structure from the second family space.

16. The apparatus of claim 15 wherein the program code creates a second virtual block that is a copy of the first virtual block.

17. The apparatus of claim 16 wherein the program code modifies the first pointer structure to associate the first snap with the second virtual block.

18. The apparatus of claim 16 wherein the program code modifies the second pointer structure to associate the second snap with the second virtual block.

19. An apparatus comprising:

a computing node that presents a plurality of production devices for storage of host application data and manages storage of the host application data on a plurality of non-volatile data storage drives, the computing node comprising program code that;

provisions a separate family space as a separate fault domain in a virtual storage space for each of the production devices, including a first family contiguous logical block address space for a first production device and a second family contiguous logical block address space for a second production device such that the logical block addresses of the first family and the second family do not overlap;

stores a first clone and a first snap of the first production device in the first family space;

stores a second clone and a second snap of the second production device in the second family space; and

recovers from a fault associated with the first production device by accessing the first snap without interrupting input-output commands to the second production device.

20. The apparatus of claim 19 wherein the program code:

recognizes that a first virtual block associated with the first snap is associated with a first pointer structure from the first family space and a second pointer structure from the second family space;

creates a second virtual block that is a copy of the first virtual block; and

modifies the first pointer structure to associate the first snap with the second virtual block.