Online initial mirror synchronization and mirror synchronization verification in storage area networks

Abstract

Systems and methods in accordance with various disclosed embodiments can manage a mirrored virtual target to synchronize the members of the virtual target and/or to verify that the members of the virtual target are synchronized. In one embodiment, a mirrored virtual target is synchronized by first provisioning at least one first internal virtual logical unit (IVLU) corresponding to at least one destination target of the mirrored target and a second IVLU corresponding to a source target of the mirrored target. A write command is first issued, via one or more internal virtual logical units, to each of the destination target members of the mirrored target. When each destination target is available to receive data, as evidenced by a returned transfer ready signal, a read command is provided to the source target via the second internal virtual logical unit. In this manner, a data path between the source and destination targets is established prior to reading data from the source target. Accordingly, the data can be read from the source target, converted to write data, and routed to the destination targets at line speed without buffering of the data. A similar process is provided to verify that the members of a mirrored target are synchronized. In one embodiment, a system and method is provided to manage incoming commands for the mirrored target while synchronizing or verifying synchronization of the mirrored target. Incoming commands can be queued as they are received and provided to the mirrored target when pending synchronization or verification commands are completed.