TRANSFERRING DATA OF A DISPERSED STORAGE NETWORK

• US 20140019579A1
• Filed: 09/17/2013
• Published: 01/16/2014
• Est. Priority Date: 11/09/2010
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: Motwani, Manish, Resch, Jason K., Baptist, Andrew, Volvovski, Ilya
• Granted Patent: US 9,590,838 B2
• Time in Patent Office: Days
• US Class Current: 709/216
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 12/02 Addressing or allocation; Relocation program address sequencing G06F9/00; arrangements for selecting an address in a digital store G11C8/00
• CPC Class Codes: G06F 2211/1057 Parity-multiple bits-RAID6, i.e. RAID 6 implementations
• CPC Class Codes: G06F 3/0614 Improving the reliability of storage systems
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

A method begins by a dispersed storage (DS) processing detecting unavailability of a storage device of a site of dispersed storage network (DSN) memory to produce an unavailable storage device. The method continues with the DS processing module reassigning a fraction of a logical address sub-range of the unavailable storage device to one or more other storage devices, rebuilding one or more logically addressable data objects to produce one or more rebuilt data objects and storing the one or more rebuilt data objects in the one or more other storage devices. When the unavailable storage device becomes available, the method continues with the DS processing module reallocating the fraction of the logical address sub-range from the one or more other storage devices to the storage device and transferring the one or more rebuilt data objects from the one or more other storage devices to the storage device.

Claims

1. A method for execution by one or more processing modules of a computing device of a dispersed storage network (DSN), the method comprises:

detecting unavailability of a storage device of a site of DSN memory to produce an unavailable storage device, wherein the DSN memory includes a plurality of sites that includes the site, the site includes a plurality of storage devices that includes the storage device, the DSN memory has a logical address range, wherein the site is assigned a logical address sub-range of the logical address range and each of the plurality of storage devices is assigned a fraction of the logical address sub-range in a storage device sequential manner; and

when the unavailable storage device is storing one or more logically addressable data objects;

reassigning, within the site, the fraction of the logical address sub-range of the unavailable storage device to one or more other storage devices of the plurality of storage devices while maintaining the storage device sequential manner of allocating the fractions of the logical address sub-range;

rebuilding the one or more logically addressable data objects to produce one or more rebuilt data objects;

storing the one or more rebuilt data objects in the one or more other storage devices;

when the unavailable storage device becomes available, reallocating the fraction of the logical address sub-range from the one or more other storage devices to the storage device; and

transferring, from the one or more other storage devices, the one or more rebuilt data objects to the storage device.

2. The method of claim 1, wherein the detecting the unavailability of the storage device comprises one of:

detecting unavailability of one or more memory devices of a plurality of memory devices associated with the storage device; and

detecting that the storage device is off-line.

3. The method of claim 1, wherein the reassigning the fraction of the logical address sub-range comprises:

dividing the fraction of the logical address sub-range into a first portion and a second portion;

reassigning the first portion to one of the one or more other storage devices having a first contiguous fraction of the logical address sub-range; and

reassigning the second portion to a second one of the one or more other storage devices having a second contiguous fraction of the logical address sub-range.

4. The method of claim 1, wherein the rebuilding the one or more logically addressable data objects comprises:

sending rebuilding requests to other sites regarding the one or more logically addressable data objects;

receiving, in response to the rebuilding requests, rebuilding data; and

rebuilding the one or more logically addressable data objects from the rebuilding data.

5. The method of claim 1, wherein the storing the one or more rebuilt data objects in the one or more other storage devices comprises:

sending one or more write requests to the one or more other storage devices regarding the one or more rebuilt data objects, wherein a write request of the one or more write requests includes a logical address within the reassigned fraction of the logical address sub-range and a corresponding one of the one or more rebuilt data objects.

6. The method of claim 1 further comprises:

detecting that the unavailable storage device is available based on one or more of;

a repair or replacement of the unavailable storage device;

the unavailable storage device coming back on-line; and

a repair or replacement of a memory device within the storage device.

7. The method of claim 1, wherein the transferring the one or more rebuilt data objects comprises:

issuing one or more write commands to the one or more other storage devices to write the one or more rebuilt data objects to the storage device;

receiving an acknowledge of successful storage of the one or more rebuilt data objects by the storage device; and

issuing a delete command to the one or more other storage devices to delete the one or more rebuilt data objects.

8. A dispersed storage (DS) processing module of a dispersed storage network (DSN), the DS processing module comprises:

a first module, when operable within a computing device, causes the computing device to;

detect unavailability of a storage device of a site of DSN memory to produce an unavailable storage device, wherein the DSN memory includes a plurality of sites that includes the site, the site includes a plurality of storage devices that includes the storage device, the DSN memory has a logical address range, wherein the site is assigned a logical address sub-range of the logical address range and each of the plurality of storage devices is assigned a fraction of the logical address sub-range in a storage device sequential manner; and

a second module, when operable within the computing device, causes the computing device to;

when the unavailable storage device is storing one or more logically addressable data objects;

reassign, within the site, the fraction of the logical address sub-range of the unavailable storage device to one or more other storage devices of the plurality of storage devices while maintaining the storage device sequential manner of allocating the fractions of the logical address sub-range;

rebuild the one or more logically addressable data objects to produce one or more rebuilt data objects;

store the one or more rebuilt data objects in the one or more other storage devices;

when the unavailable storage device becomes available, reallocate the fraction of the logical address sub-range from the one or more other storage devices to the storage device; and

transfer, from the one or more other storage devices, the one or more rebuilt data objects to the storage device.

9. The DS processing module of claim 8, wherein the first module functions to detect the unavailability of the storage device by one of:

detecting unavailability of one or more memory devices of a plurality of memory devices associated with the storage device; and

detecting that the storage device is off-line.

10. The DS processing module of claim 8, wherein the second module functions to reassign the fraction of the logical address sub-range by:

dividing the fraction of the logical address sub-range into a first portion and a second portion;

reassigning the first portion to one of the one or more other storage devices having a first contiguous fraction of the logical address sub-range; and

reassigning the second portion to a second one of the one or more other storage devices having a second contiguous fraction of the logical address sub-range.

11. The DS processing module of claim 8, wherein the second module functions to rebuild the one or more logically addressable data objects by:

sending rebuilding requests to other sites regarding the one or more logically addressable data objects;

receiving, in response to the rebuilding requests, rebuilding data; and

rebuilding the one or more logically addressable data objects from the rebuilding data.

12. The DS processing module of claim 8, wherein the second module functions to store the one or more rebuilt data objects in the one or more other storage devices by:

sending one or more write requests to the one or more other storage devices regarding the one or more rebuilt data objects, wherein a write request of the one or more write requests includes a logical address within the reassigned fraction of the logical address sub-range and a corresponding one of the one or more rebuilt data objects.

13. The DS processing module of claim 8 further comprises:

the second module, when operable within the computing device, further causes the computing device to;

detect that the unavailable storage device is available based on one or more of;

a repair or replacement of the unavailable storage device;

the unavailable storage device coming back on-line; and

a repair or replacement of a memory device within the storage device.

14. The DS processing module of claim 8, wherein the second module functions to transfer the one or more rebuilt data objects by:

issuing one or more write commands to the one or more other storage devices to write the one or more rebuilt data objects to the storage device;

receiving an acknowledge of successful storage of the one or more rebuilt data objects by the storage device; and

issuing a delete command to the one or more other storage devices to delete the one or more rebuilt data objects.