Patent ID: 6996691
Filing Date: 2006-02-07
Classification: G06F,H04L,Y10S

Abstract:
1. A method for copying data, written by a host computer to a local data storage array, to a backup copy of the data on a remote storage system, wherein a local array controller, connected to the local data storage array, is coupled to a remote array controller connected to the remote storage system, the method comprising the steps of: assigning a first current sequence number as the look-ahead limit for a write command associated with the data; upon command completion, storing a second current sequence number as the write command sequence number; placing the command in a queue; sending the command sequence number and look-ahead limit, with the command associated therewith, to the remote array controller; on reception of the received command by the remote array controller, executing the command at the remote controller; when a write operation completes at the remote array controller, then continuing to process said outstanding commands by directing each said command in the waiting queue back to the sending step.