Appendix; Scsi Write Acceleration And Tape Acceleration; Scsi Write Acceleration - Cisco MDS 9000 series Configuration Manual

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SCSI Write Acceleration and Tape Acceleration

This appendix describes the concepts of SCSI write acceleration, tape acceleration, and compression.
This appendix includes the following sections:
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SCSI Write Acceleration

The SCSI write acceleration feature enables you to significantly improve application write performance
when storage traffic is routed over wide area networks using FCIP or Fibre Channel. When write
acceleration is enabled, WAN throughput is maximized by minimizing the impact of WAN latency for
write operations.
In Figure
while the WRITE command with write acceleration only requires one RTT. The maximum sized Transfer
Ready is sent from the host side of the FCIP or Fibre Channel link back to the host before the WRITE
command reaches the target. This enables the host to start sending the write data without waiting for the
long latency over the FCIP or Fibre Channel link of the WRITE command and Transfer Ready. It also
eliminates the delay caused by multiple Transfer Readys needed for the exchange going over the FCIP
or Fibre Channel link.
OL-20708-01, Cisco MDS NX-OS Release 5.0(1a)
SCSI Write Acceleration, page A-1
SCSI Tape Acceleration, page A-2
A-1, the WRITE command without write acceleration requires two round-trip transfers (RTT),
A P P E N D I X
Cisco MDS 9000 Family I/O Accelerator Configuration Guide
A
A-1