Patent ID: 7716381
Filing Date: 2010-05-11
Classification: G06F,H04L

Abstract:
1. In a Storage Area Network (SAN), a method for continuously providing Input/Output completion information for a particular logical drive, comprising: timestamping an I/O command destined for the particular logical drive with a first time prior to transmission of the I/O command across the SAN; recording a second time when an I/O completion is received from the SAN; calculating an I/O command completion time by computing a time difference between the first time and the second time; determining a particular range of time that the calculated I/O command completion time falls within; identifying a bucket representing the particular range of time from a plurality of buckets associated with the particular logical drive each bucket representing a unique range of time and containing a count of I/O commands destined for the particular logical drive that are completed within the range of time represented by the bucket; incrementing the count of I/O commands within the identified bucket; calculating an average I/O command completion time for the particular logical drive based on the plurality of buckets and counts contained therein; and increasing or decreasing a number of outstanding I/O commands associated with the particular logical drive based on the calculated average I/O command completion time as compared to a pre-determined threshold.