Mapping storage of data in a dispersed storage network

• US 10,324,623 B2
• Filed: 01/12/2017
• Issued: 06/18/2019
• Est. Priority Date: 01/04/2013
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Resch, Jason K., Dhuse, Greg
• Primary Examiner(s): Guyton, Philip
• Application Number:
  US15/405,004
• Publication Number:
  US 20170123669A1
• Time in Patent Office: 887 Days
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0629 Configuration or reconfiguration of storage systems
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A method includes encoding a data segment of a data object into a set of encoded data slices. The set of encoded data slices includes “n” number of encoded data slices. The method further includes generating a set of slice names for the set of encoded data slices. The method further includes selecting “m” encoded data slices of the set of encoded data slices to output for storage in DSN memory. The method further includes selecting “m” storage units of “p” storage units of the DSN memory for storing the “m” encoded data slices. The method further includes mapping “m” slice names of the “m” encoded data slices to DSN addresses of the “m” storage units to create mapped slice names. The method further includes outputting, in accordance with the mapped slice names, the “m” encoded data slices to the “m” storage units for storage therein.

Claims

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

encoding a data segment of a data object into a set of encoded data slices, wherein the set of encoded data slices includes “

n”

number of encoded data slices;

generating a set of slice names for the set of encoded data slices;

selecting “

m”

encoded data slices of the set of encoded data slices to output for storage in DSN memory, wherein “

m”

is less than “

n” and

wherein “

m”

is equal to or greater than a decode threshold;

selecting “

m”

storage units of “

p”

storage units of the DSN memory for storing the “

m”

encoded data slices;

mapping “

m”

slice names of the “

m”

encoded data slices to DSN addresses of the “

m”

storage units to create mapped slice names, wherein the mapping of the “

m”

slice names to DSN addresses of the “

m”

storage units includes accessing a storage selection table, wherein the storage selection table includes a DSN address range field, a target set field, and a plurality of target slice fields, wherein a target slice field of the plurality of target slice fields links an encoded data slice of the set of encoded data slices to a particular storage unit of the “

m”

storage units; and

outputting, in accordance with the mapped slice names, the “

m”

encoded data slices to the “

m”

storage units for storage therein.

2. The method of claim 1, wherein the selecting the “

m”

storage units comprises;

identifying at least some of the “

p”

storage units that each have a DSN address range that includes a DSN address that is associated with a source name of the set of slice names; and

selecting the “

m”

storage units from the at least some of the “

p”

storage units.

3. The method of claim 1 further comprises:

determining that an encoded data slice of the “

m”

encoded data slices was not successfully stored by a storage unit of the “

m”

storage units;

identifying another encoded data slice of the “

n”

encoded data slices that was not part of the “

m”

encoded data slices;

mapping a slice name of the other encoded data slice to the DSN address of the storage unit; and

outputting the encoded data slice to the storage unit for storage therein.

4. The method of claim 1 further comprises:

encoding a first set of data segments of the data object into first sets of encoded data slices, wherein each of the first sets of encoded data slices includes “

n”

number of encoded data slices;

generating first sets of slice names for the first sets of encoded data slices;

selecting “

m”

encoded data slices of each set of the first sets of encoded data slices to output for storage in DSN memory, wherein “

m”

is less than “

n” and

wherein “

m”

is equal to or greater than a decode threshold;

selecting the “

m”

storage units of “

p”

storage units of the DSN memory for storing the “

m”

encoded data slices of each set of the first set of encoded data slices;

mapping “

m”

slice names of each set of the first set of slice names that correspond to the “

m”

encoded data slices of each set of the first sets of encoded data slices to DSN addresses of the “

m”

storage units to create mapped slice names; and

outputting, in accordance with the mapped slice names, the “

m”

encoded data slices of each set of the first sets of encoded data slices to the “

m”

storage units for storage therein.

5. The method of claim 4 further comprises:

encoding a second set of data segments of the data object into second sets of encoded data slices, wherein each of the second sets of encoded data slices includes the “

n”

number of encoded data slices;

generating second sets of slice names for the second sets of encoded data slices;

selecting “

x”

encoded data slices of each set of the second sets of encoded data slices to output for storage in DSN memory, wherein “

x”

is less than “

n” and

wherein “

x”

is equal to or greater than a decode threshold;

selecting “

x”

storage units of the “

p”

storage units of the DSN memory for storing the “

x”

encoded data slices of each set of the second set of encoded data slices;

mapping “

x”

slice names of each set of the second set of slice names that correspond to the “

x”

encoded data slices of each set of the second sets of encoded data slices to DSN addresses of the “

x”

storage units to create mapped slice names; and

outputting, in accordance with the mapped slice names, the “

x”

encoded data slices of each set of the second sets of encoded data slices to the “

x”

storage units for storage therein.

6. A computing device of a dispersed storage network (DSN), the computing device comprises:

an interface;

memory; and

a processing module operably coupled to the interface and to the memory, wherein the processing module is operable to;

encode a data segment of a data object into a set of encoded data slices, wherein the set of encoded data slices includes “

n”

number of encoded data slices;

generate a set of slice names for the set of encoded data slices;

select “

m”

encoded data slices of the set of encoded data slices to output for storage in DSN memory, wherein “

m”

is less than “

n” and

wherein “

m”

is equal to or greater than a decode threshold;

select “

m”

storage units of “

p”

storage units of the DSN memory for storing the “

m”

encoded data slices;

map “

m”

slice names of the “

m”

encoded data slices to DSN addresses of the “

m”

storage units to create mapped slice names, wherein the mapping of the “

m”

slice names to DSN addresses of the “

m”

storage units includes accessing a storage selection table, wherein the storage selection table includes a DSN address range field, a target set field, and a plurality of target slice fields, wherein a target slice field of the plurality of target slice fields links an encoded data slice of the set of encoded data slices to a particular storage unit of the “

m”

storage units; and

output, in accordance with the mapped slice names, the “

m”

encoded data slices to the “

m”

storage units for storage therein.

7. The computing device of claim 6, wherein the processing module is further operable to select the “

m”

storage units by;

identifying at least some of the “

p”

storage units that each have a DSN address range that includes a DSN address that is associated with a source name of the set of slice names; and

selecting the “

m”

storage units from the at least some of the “

p”

storage units.

8. The computing device of claim 6, wherein the processing module is further operable to:

determine that an encoded data slice of the “

m”

encoded data slices was not successfully stored by a storage unit of the “

m”

storage units;

identify another encoded data slice of the “

n”

encoded data slices that was not part of the “

m”

encoded data slices;

map a slice name of the other encoded data slice to the DSN address of the storage unit; and

output the encoded data slice to the storage unit for storage therein.

9. The computing device of claim 6, wherein the processing module is further operable to:

encode a first set of data segments of the data object into first sets of encoded data slices, wherein each of the first sets of encoded data slices includes “

n”

number of encoded data slices;

generate first sets of slice names for the first sets of encoded data slices;

select “

m”

encoded data slices of each set of the first sets of encoded data slices to output for storage in DSN memory, wherein “

m”

is less than “

n” and

wherein “

m”

is equal to or greater than a decode threshold;

select the “

m”

storage units of “

p”

storage units of the DSN memory for storing the “

m”

encoded data slices of each set of the first set of encoded data slices;

map “

m”

slice names of each set of the first set of slice names that correspond to the “

m”

encoded data slices of each set of the first sets of encoded data slices to DSN addresses of the “

m”

storage units to create mapped slice names; and

output, in accordance with the mapped slice names, the “

m”

encoded data slices of each set of the first sets of encoded data slices to the “

m”

storage units for storage therein.

10. The computing device of claim 9, wherein the processing module is further operable to:

encode a second set of data segments of the data object into second sets of encoded data slices, wherein each of the second sets of encoded data slices includes the “

n”

number of encoded data slices;

generate second sets of slice names for the second sets of encoded data slices;

selecting “

x”

encoded data slices of each set of the second sets of encoded data slices to output for storage in DSN memory, wherein “

x”

is less than “

n” and

wherein “

x”

is equal to or greater than a decode threshold;

select “

x”

storage units of the “

p”

storage units of the DSN memory for storing the “

x”

encoded data slices of each set of the second set of encoded data slices;

map “

x”

slice names of each set of the second set of slice names that correspond to the “

x”

encoded data slices of each set of the second sets of encoded data slices to DSN addresses of the “

x”

storage units to create mapped slice names; and

output, in accordance with the mapped slice names, the “

x”

encoded data slices of each set of the second sets of encoded data slices to the “

x”

storage units for storage therein.