Patent ID: 9110597
Filing Date: 2015-08-18
Classification: G06F

Abstract:
1. A method of retrieving data blocks in a storage area network, the method comprising: in response to an input/output (I/O) operation to be performed with respect to a storage device, determining whether any of a plurality of paths to the storage device is available for the I/O operation, wherein the determining is based on determining which of the plurality of paths has a corresponding range of block identifiers that corresponds to a block requested by the I/O operation; in response to determining that a particular one of the plurality of paths is available for the I/O operation, selecting the particular path to the storage device, wherein determining that the particular path is available comprises determining that a number of blocks serviced by the particular path has not exceeded a predefined threshold; retrieving a first number of sequential data blocks from the storage device along the particular path; and after the retrieving, selecting a second one of the plurality of paths for retrieving subsequent sequential data blocks from the storage device; in response to determining that none of the plurality of paths is available for the I/O operation, selecting another of the plurality of paths based on comparing turnaround times of respective ones of at least some of the plurality of paths; monitoring turnaround times for blocks communicated over the plurality of paths; and varying the predefined threshold based on the monitored turnaround times.