Path selection to read or write data

摘要

In one aspect, a method includes determining a number of read blocks pending for each path from a host to a logical device, determining a number of write blocks pending for each path from the host to the logical device, determining one or more factors associated with time for each path from the host to the logical device and selecting a path from the host to the logical device to read or write data using the number of read blocks pending, the number of write blocks pending and the one or more factors associated with time.

主权项

1. A method comprising:
determining a number of read blocks pending for each path from a host to a logical device; determining a number of write blocks pending for each path from the host to the logical device; determining one or more factors associated with time for each path from the host to the logical device, wherein determining one or more factors associated with time for each path comprises determining a weighted average time to read a single block for each path from the host to the logical device or a weighted average time to write a single block for each path from the host to the logical device, wherein determining a weighted average time to read a single block for each path comprises:
assigning weights to each of the N blocks read for the path including assigning larger weight to more recently read blocks,generating weighted read times for each of the last N blocks read for the path by multiplying an actual reading time by the corresponding weight; andcalculating an average of the weighted read times; and selecting a path from the host to the logical device to read or write data using the number of read blocks pending, the number of write blocks pending and the one or more factors associated with time.