Deadline-Based Scheduling in a Distributed File System

摘要

Approaches for retrieving files from a replicated file system. A component receives, from a requestor, a request for a copy of a data unit. The component identifies a plurality of storage nodes that each stores a complete copy of the data unit. The component sends, to the plurality of storage nodes, an instruction to retrieve a copy of the data unit within a specified period of time. At each storage node receiving an instruction, a determination of whether the copy of the data unit may be retrieved within the specified period of time is made, and if so, the copy of the data unit is provided to the component only if the copy of the data unit was actually retrieved within the specified period. The component provides the first copy of the data unit it receives to the requestor and discards any subsequently received copies of the data unit.

主权项

1. A system for retrieving a file from a replicated file system, comprising:
one or more processors; and one or more machine-readable mediums storing one or more sequences of instructions, which when executed by the one or more processors, causes:
in response to a software component receiving, from a requestor, a request for a copy of a data unit, identifying a plurality of storage nodes that each stores a complete copy of the data unit;the software component sending, in parallel to each of the plurality of storage nodes, an instruction to retrieve a copy of the data unit within a specified period of time;at each of the plurality of storage nodes, performing:
determining whether the copy of the data unit may be retrieved within the specified period of time, andupon determining that the copy of the data unit may be retrieved within the specified period of time, (a) retrieving the copy of the data unit, and (b) providing the copy of the data unit to the software component only if the copy of the data unit was actually retrieved within the specified period of time; andat the software component, providing the first copy of the data unit received to the requestor and discarding any subsequently received copies of the data unit.