Patent ID: 7363541

Claim:
A device capable of usage in a storage system including an initiator, a primary target, and a secondary target, the device being capable of configuration for asynchronous remote mirroring functionality and comprising: a target controller capable of communicating with the initiator and performing operations requested by the initiator; and a process on the target controller capable of receiving a stream of command requests from the initiator, performing the requested commands, relaying the requested commands to a secondary target while ensuring precedence graph equivalence between received and relayed commands, the process tracking outstanding write tasks, marking write tasks with task attributes according to changes in number of outstanding write tasks, and embedding task attributes in the relayed commands capable of increasing concurrency in commands performed by the secondary target, wherein the target controller is a Small Computer Systems Interface (SCSI) device and the task attributes are SCS/task attributes including Simple, Ordered, Head of Queue, and Auto Contingent Allegiance (ACA) task attributes.