Mapping storage slots to a set of storage units

1. A method for execution by one or more computing devices of a storage network, the method comprises:

determining an information dispersal algorithm width number;

determining a number of primary storage slots from a number of storage slots associated with a set of storage units deployed across multiple sites, wherein the number of primary storage slots is equal to or greater than the information dispersal algorithm width number;

determining a mapping of primary storage slots to storage units of the set of storage units;

sending configuration information to the set of storage units, wherein the configuration information includes the mapping; and

storing a set of encoded data slices in the primary storage slots of the set of storage units in accordance with the configuration information, wherein a data segment of data is dispersed storage error encoded into the set of encoded data slices in accordance with the information dispersal algorithm width number and a decode threshold number, and wherein the decode threshold number of encoded data slices are needed to reconstruct the data segment.

2. The method of claim 1 , wherein the determining the information dispersal algorithm width number comprises:

obtaining a site failure toleration goal number; and

determining the information dispersal algorithm width number based on the site failure toleration goal number and the mapping of primary storage slots to the storage units at each site such that when a number of failed sites of the multiple sites is less than or equal to the site failure toleration goal number for a particular time period, the decode threshold number of encoded data slices are available at non-failed sites of the multiple sites.

3. The method of claim 1 , wherein the determining the number of the primary storage slots comprises utilizing a predetermination.

4. The method of claim 1 , wherein the determining the mapping of the primary storage slots to storage units comprises:

determining a number of storage units at each site of the multiple sites;

determining a system primary slot distribution scheme; and

determining the mapping based on the number of storage units for each site and the system primary slot distribution scheme.

5. The method of claim 1 , wherein the determining the mapping of the primary storage slots to storage units comprises:

assigning, as the primary storage slots, available storage slots from each storage unit of the set of storage units at each site of the multiple sites in a substantially even distribution such that each site of the multiple sites has approximately a same number of primary storage slots.

6. The method of claim 1 , wherein the configuration information comprises:

storage network addressing information for storing encoded data slices in the set of storage units.

7. The method of claim 1 , wherein the storing the set of encoded data slices comprises:

issuing write slice requests to the storage units in accordance with the mapping, wherein the write slice requests includes the set of encoded data slices.

8. The method of claim 7 further comprises:

receiving write responses from the set of storage units;

determining a failure when less than the information dispersal algorithm width number of favorable write responses are received within a response timeframe; and

in response to the determining the failure, issuing an additional write slice request to another storage slot of the number of storage slots, wherein the additional write slice request includes an encoded data slice of the set of encoded data slices associated with the failure.

9. The method of claim 8 , wherein determining the other storage slot comprises:

determining a storage unit of the set of storage units that is associated with a favorable write response of the write responses;

determining an available storage slot of the number of storage slots associated with the storage unit; and

assigning the available storage slot as the other storage slot.

10. The method of claim 8 , wherein determining the other storage slot comprises accessing a list of available storage slots.

11. A computing device comprises:

memory;

an interface; and

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

determine an information dispersal algorithm width number;

determine a number of primary storage slots from a number of storage slots associated with a set of storage units deployed across multiple sites, wherein the number of primary storage slots is equal to or greater than the information dispersal algorithm width number;

determine a mapping of primary storage slots to storage units of the set of storage units;

send, via the interface, configuration information to the set of storage units, wherein the configuration information includes the mapping; and

facilitate storage of a set of encoded data slices in the primary storage slots of the set of storage units in accordance with the configuration information, wherein a data segment of data is dispersed storage error encoded into the set of encoded data slices in accordance with the information dispersal algorithm width number and a decode threshold number, and wherein the decode threshold number of encoded data slices are needed to reconstruct the data segment.

12. The computing device of claim 11 , wherein the determining the information dispersal algorithm width number comprises:

obtaining a site failure toleration goal number; and

determining the information dispersal algorithm width number based on the site failure toleration goal number and the mapping of primary storage slots to the storage units at each site such that when a number of failed sites of the multiple sites is less than or equal to the site failure toleration goal number for a particular time period, the decode threshold number of encoded data slices are available at non-failed sites of the multiple sites.

13. The computing device of claim 11 , wherein the determining the number of the primary storage slots comprises utilizing a predetermination.

14. The computing device of claim 11 , wherein the determining the mapping of the primary storage slots to storage units comprises:

determining a number of storage units at each site of the multiple sites;

determining a system primary slot distribution scheme; and

determining the mapping based on the number of storage units for each site and the system primary slot distribution scheme.

15. The computing device of claim 11 , wherein the determining the mapping of the primary storage slots to storage units comprises:

assigning, as the primary storage slots, available storage slots from each storage unit of the set of storage units at each site of the multiple sites in a substantially even distribution such that each site of the multiple sites has approximately a same number of primary storage slots.

16. The computing device of claim 11 , wherein the configuration information comprises:

storage network addressing information for storing encoded data slices in the set of storage units.

17. The computing device of claim 11 , wherein the storing the set of encoded data slices comprises:

issuing write slice requests to the storage units in accordance with the mapping, wherein the write slice requests includes the set of encoded data slices.

18. The computing device of claim 17 further comprises:

receiving write responses from the set of storage units;

determining a failure when less than the information dispersal algorithm width number of favorable write responses are received within a response timeframe; and

in response to the determining the failure, issuing an additional write slice request to another storage slot of the number of storage slots, wherein the additional write slice request includes an encoded data slice of the set of encoded data slices associated with the failure.

19. The computing device of claim 18 , wherein determining the other storage slot comprises:

determining a storage unit of the set of storage units that is associated with a favorable write response of the write responses;

determining an available storage slot of the number of storage slots associated with the storage unit; and

assigning the available storage slot as the other storage slot.

20. The computing device of claim 18 , wherein determining the other storage slot comprises accessing a list of available storage slots.