Validating stored encoded data slice integrity in a dispersed storage network
An encoded data slice is received for storage by a dispersed storage and task (DST) execution unit. A plurality of initial integrity values are generated by executing a plurality of integrity check algorithms on the encoded data slice. The encoded data slice and the plurality of initial integrity values are stored in a memory of the DST execution unit. A subset of the plurality of integrity check algorithms are selected in response to a request to retrieve the encoded data slice. At least one final integrity value is generated by executing the subset of the plurality of integrity check algorithms on the encoded data slice stored in memory. An integrity status is generated by comparing the at least one final integrity value to the corresponding subset of the plurality of initial integrity values.
1. A method for execution by a dispersed storage and task (DST) execution unit that includes a processor, the method comprises:
for a write request regarding an encoded data slice:
receiving the encoded data slice for storage by the DST execution unit;
generating a plurality of initial integrity values for the encoded data slice by executing a plurality of integrity check algorithms on the encoded data slice;
storing the encoded data slice and the plurality of initial integrity values in a memory of the DST execution unit; and
for a read request regarding the encoded data slice:
selecting a subset of the plurality of integrity check algorithms in response to the read request;
generating at least one final integrity value by executing the subset of the plurality of integrity check algorithms on the encoded data slice stored in the memory;
generating an integrity status by comparing the at least one final integrity value to the corresponding subset of the plurality of initial integrity values; and
when the integrity status is favorable, sending the encoded data slice to a requesting computing device in response to the read request.
2. The method of claim 1 , further comprising selecting the plurality of integrity check algorithms to be executed on the encoded data slice.
3. The method of claim 2 , wherein the plurality of integrity check algorithms are selected based on at least one of: a processing resource availability level, a desired false-negative probability level, or an algorithm computational efficiency level.
4. The method of claim 2 , wherein a first integrity check algorithm is more error-prone than a second integrity check algorithm, wherein the plurality of integrity check algorithms selected includes the first integrity check algorithm in response to determining that processing resource availability is low, and wherein the plurality of integrity check algorithms selected includes the second integrity check algorithm in response to determining that sufficient processing resources are available.
5. The method of claim 2 , wherein a first integrity check algorithm is faster than a second integrity check algorithm, and wherein the plurality of integrity check algorithms selected includes the first integrity check algorithm in response to determining that a low desired latency level is required.
6. The method of claim 1 further comprising:
generating a plurality of priority levels corresponding to each of the plurality of integrity check algorithms;
wherein the plurality of integrity check algorithms are executed in an order based on the plurality of priority levels.
7. The method of claim 1 further comprising storing a plurality of identifiers corresponding to the plurality of integrity check algorithms in the memory.
8. The method of claim 1 wherein the subset of the plurality of integrity check algorithms is a non-null proper subset that is selected based on at least one of: an available resource level, a required retrieval performance level, and a recovery desired maximum false-negative probability level.
9. The method of claim 1 wherein the integrity status indicates a favorable comparison when a result of the comparison indicates that the plurality of initial integrity values and the at least one final integrity value are substantially identical, and wherein the integrity status indicates an unfavorable comparison when a result of the comparison indicates that the corresponding subset of the plurality of initial integrity values and the at least one final integrity value are not substantially identical.
10. The method of claim 1 , wherein the sending further comprises sending the integrity status.
11. A processing system of a dispersed storage and task (DST) execution unit comprises:
at least one processor;
a memory that stores operational instructions, that when executed by the at least one processor cause the processing system to:
for a write request regarding an encoded data slice:
receive the encoded data slice for storage by the DST execution unit;
generate a plurality of initial integrity values for the encoded data slice by executing a plurality of integrity check algorithms on the encoded data slice;
store the encoded data slice and the plurality of initial integrity values in a memory of the DST execution unit; and
for a read request regarding the encoded data slice:
select a subset of the plurality of integrity check algorithms in response to the read request;
generate at least one final integrity value by executing the subset of the plurality of integrity check algorithms on the encoded data slice stored in the memory;
generate an integrity status by comparing the at least one final integrity value to the corresponding subset of the plurality of initial integrity values; and
when the integrity status is favorable, sending the encoded data slice to a requesting computing device in response to the read request.
12. The processing system of claim 11 , further comprising selecting the plurality of integrity check algorithms to be executed on the encoded data slice.
13. The processing system of claim 12 , wherein the plurality of integrity check algorithms are selected based on at least one of: a processing resource availability level, a desired false-negative probability level, or an algorithm computational efficiency level.
14. The processing system of claim 12 , wherein a first integrity check algorithm is more error-prone than a second integrity check algorithm, wherein the plurality of integrity check algorithms selected includes the first integrity check algorithm in response to determining that processing resource availability is low, and wherein the plurality of integrity check algorithms selected includes the second integrity check algorithm in response to determining that sufficient processing resources are available.
15. The processing system of claim 12 , wherein a first integrity check algorithm is faster than a second integrity check algorithm, and wherein the plurality of integrity check algorithms selected includes the first integrity check algorithm in response to determining that a low desired latency level is required.
16. The processing system of claim 11 further comprising:
generating a plurality of priority levels corresponding to each of the plurality of integrity check algorithms;
wherein the plurality of integrity check algorithms are executed in an order based on the plurality of priority levels.
17. The processing system of claim 11 further comprising storing a plurality of identifiers corresponding to the plurality of integrity check algorithms in the memory.
18. The processing system of claim 11 wherein the subset of the plurality of integrity check algorithms is a non-null proper subset that is selected based on at least one of: an available resource level, a required retrieval performance level, and a recovery desired maximum false-negative probability level.
19. The processing system of claim 11 wherein the integrity status indicates a favorable comparison when a result of the comparison indicates that the plurality of initial integrity values and the at least one final integrity value are substantially identical, and wherein the integrity status indicates an unfavorable comparison when a result of the comparison indicates that the at least one initial integrity value and the at least one final integrity value are not substantially identical.
20. A non-transitory computer readable storage medium comprises:
at least one memory section that stores operational instructions that, when executed by a processing system of a dispersed storage network (DSN) that includes a processor and a memory, causes the processing system to:
for a write request regarding an encoded data slice:
receive the encoded data slice for storage;
generate a plurality of initial integrity values for the encoded data slice by executing a plurality of integrity check algorithms on the encoded data slice;
store the encoded data slice and the plurality of initial integrity values in a memory of a dispersed storage and task (DST) execution unit; and
for a read request regarding the encoded data slice:
select a subset of the plurality of integrity check algorithms in response to the read request;
generate at least one final integrity value by executing the subset of the plurality of integrity check algorithms on the encoded data slice stored in the memory;
generate an integrity status by comparing the at least one final integrity value to the corresponding subset of the plurality of initial integrity values; and
when the integrity status is favorable, sending the encoded data slice to a requesting computing device in response to the read request.