Managing distributed system performance using accelerated data retrieval operations
A distributed system is adapted to manage the performance of distributed processes. In one aspect, multiple stripes associated with a data item are stored in a distributed storage. The stored stripes include one or more stripes of redundancy information for the data item. A distributed process including at least one task is performed. During performance of the distributed process, a determination is made as to whether to perform an accelerated data retrieval operation. Responsive to a determination to perform an accelerated data retrieval operation, at least one of the one or more stripes of redundancy information for the data item is requested from the distributed storage. Other stripes associated with the data item may also be requested from the distributed storage. After a sufficient subset of stripes associated with the data item is received, the data item is reconstructed using the subset.
1. A method for managing performance of a distributed storage system, the method comprising:
storing, in a plurality of storage devices of the distributed storage system, a plurality of stripes associated with a data item, the plurality of stripes generated according to a coding scheme, wherein the coding scheme generates a number of stripes associated with the data item that is more than a minimum number of stripes needed to reconstruct the data item, and wherein the plurality of stripes includes a plurality of copies of at least one stripe;
performing a distributed process including a task that requires retrieval of the data item from the distributed storage system; and
responsive to determining that a processing speed associated with the task does not meet a threshold, performing an accelerated data retrieval operation by:
requesting more than the minimum number of stripes needed to reconstruct the data item from at least two of the plurality of storage devices of the distributed storage system, the requested stripes including at least two copies of at least one stripe;
determining whether at least the minimum number of stripes required to reconstruct the data item has been received; and
responsive to a determination that at least the minimum number of stripes required to reconstruct the data item has been received, reconstructing the data item.
2. The method of claim 1 wherein:
the plurality of stripes associated with the data item is generated according to an error correction coding scheme.
3. The method of claim 1 wherein:
each stripe in the plurality of stripes comprises redundancy information.
4. The method of claim 1 wherein:
the plurality of stripes comprises at least one redundancy stripe.
5. The method of claim 1 wherein:
the stripes of the plurality of stripes are each stored on a different storage device of the distributed storage system.
6. The method of claim 1 further comprising:
storing a plurality of copies of the plurality of stripes associated with the data item in the distributed storage system, and
wherein performing the accelerated data retrieval operation further comprises requesting the plurality of copies of the plurality of stripes associated with the data item from the distributed storage system.
7. The method of claim 1 wherein:
the distributed process comprises a plurality of additional tasks, each of the plurality of additional tasks having a respective processing speed, each respective processing speed comprising an amount of data processed by the respective additional task divided by the pre-defined time, an average processing speed of the plurality of additional tasks comprising a sum of the processing speeds of the additional tasks divided by the number of additional tasks; and
the threshold comprises the average processing speed of the plurality of additional tasks.
8. The method of claim 1 wherein:
the distributed process comprises a plurality of additional tasks, each of the plurality of additional tasks having a respective processing speed, each respective processing speed comprising an amount of data processed by the respective additional task divided by the pre-defined time, an average processing speed of the plurality of additional tasks comprising a sum of the processing speeds of the additional tasks divided by the number of additional tasks; and
the threshold comprises a fraction of the average processing speed of the plurality of additional tasks.
9. The method of claim 1 wherein:
the distributed process comprises a plurality of additional tasks, each of the plurality of additional tasks having a respective processing speed, each respective processing speed comprising an amount of data processed by the respective additional task divided by the pre-defined time; and
the threshold comprises a selected additional task's processing speed, the selected additional task selected for having a slowest processing speed of the plurality of additional tasks.
10. A non-transitory computer readable storage medium executing computer program instructions for managing performance of a distributed storage system, the computer program instructions comprising instructions for:
storing, in a plurality of storage devices of the distributed storage system, a plurality of stripes associated with a data item, the plurality of stripes generated according to a coding scheme, wherein the coding scheme generates a number of stripes associated with the data item that is more than a minimum number of stripes needed to reconstruct the data item, and wherein the plurality of stripes includes a plurality of copies of at least one stripe;
performing a distributed process including a task that requires retrieval of the data item from the distributed storage system; and
responsive to determining that a processing speed associated with the task does not meet a threshold, performing an accelerated data retrieval operation by:
requesting more than the minimum number of stripes needed to reconstruct the data item from at least two of the plurality of storage devices of the distributed storage system, the requested stripes including at least two copies of at least one stripe;
determining whether at least the minimum number of stripes required to reconstruct the data item has been received; and
responsive to a determination that at least the minimum number of stripes required to reconstruct the data item has been received, reconstructing the data item.
11. The medium of claim 10 wherein:
the plurality of stripes associated with the data item is generated according to an error correction coding scheme.
12. The medium of claim 10 wherein:
each stripe in the plurality of stripes comprises redundancy information for the data item.
13. The medium of claim 10 wherein:
the plurality of stripes comprises at least one redundancy stripe.
14. The medium of claim 10 wherein:
the stripes of the plurality of stripes are each stored on a different storage device of the distributed storage system.
15. The medium of claim 10 wherein the instructions further comprise instructions for:
storing a plurality of copies of the plurality of stripes associated with the data item in the distributed storage system, and
wherein performing the accelerated data retrieval operation further comprises requesting the plurality of copies of the plurality of stripes associated with the data item from the distributed storage system.
16. The medium of claim 10 wherein:
the distributed process comprises a plurality of additional tasks, each of the plurality of additional tasks having a respective processing speed, each respective processing speed comprising an amount of data processed by the respective additional task divided by the pre-defined time, an average processing speed of the plurality of additional tasks comprising a sum of the processing speeds of the additional tasks divided by the number of additional tasks; and
the threshold comprises the average processing speed of the plurality of additional tasks.
17. The medium of claim 10 wherein:
the distributed process comprises a plurality of additional tasks, each of the plurality of additional tasks having a respective processing speed, each respective processing speed comprising an amount of data processed by the respective additional task divided by the pre-defined time, an average processing speed of the plurality of additional tasks comprising a sum of the processing speeds of the additional tasks divided by the number of additional tasks; and
the threshold comprises a fraction of the average processing speed of the plurality of additional tasks.
18. The medium of claim 10 wherein:
the distributed process comprises a plurality of additional tasks, each of the plurality of additional tasks having a respective processing speed, each respective processing speed comprising an amount of data processed by the respective additional task divided by the pre-defined time; and
the threshold comprises a selected additional task's processing speed, the selected additional task selected for having a slowest processing speed of the plurality of additional tasks.
19. A system comprising:
a computer readable storage medium storing processor-executable computer program instructions for managing performance of a distributed storage system, the instructions comprising instructions for:
storing, in a plurality of storage devices of the distributed storage system, a plurality of stripes associated with a data item, the plurality of stripes generated according to a coding scheme, wherein the coding scheme generates a number of stripes associated with the data item that is more than a minimum number of stripes needed to reconstruct the data item, and wherein the plurality of stripes includes a plurality of copies of at least one stripe;
performing a distributed process including a task that requires retrieval of the data item from the distributed storage system; and
responsive to determining that a processing speed associated with the task does not meet a threshold, performing an accelerated data retrieval operation by:
requesting more than the minimum number of stripes needed to reconstruct the data item from at least two of the plurality of storage devices of the distributed storage system, the requested stripes including at least two copies of at least one stripe;
determining whether at least the minimum number of stripes required to reconstruct the data item has been received; and
responsive to a determination that at least the minimum number of stripes required to reconstruct the data item has been received, reconstructing the data item.
20. The system of claim 19 wherein:
the plurality of stripes associated with the data item is generated according to an error correction coding scheme.