Write acceleration responds locally to the transfer_ready SCSI command rather than let it flow all the way across the FCIP link and then back. The transfer_ready command precipitates a flow of write SCSI commands, so by responding to it locally, the actual data gets flowing faster. After acknowledging the Xfer_Rdy, the MDS's then buffer it and send it across to get the acknowledgement. The end devices don't know it is the MDS's that are in the middle taking care of this. The key is that the initiating device is able to get the write commands out faster. The caveat to WA is that the link bounces when you add it to the configuration. Also, it is important to check which replication methods have been certified. For example, SRDF benefits from WA but SANCopy does not.
