S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Configuring Fibre Channel Write Acceleration
The Storage Services Module (SSM) supports Fibre Channel write acceleration on Cisco MDS 9000
Family switches running Cisco MDS SAN-OS Release 2.0(2b) and later.
This chapter includes the following sections:
Fibre Channel Write Acceleration
Fibre Channel write acceleration minimizes application latency or reduces transactions per second over
long distances. For synchronous data replication, Fibre Channel write acceleration increases the distance
of replication or reduces effective latency to improve performance. To take advantage of this feature,
both the initiator and target devices must be directly attached to an SSM.
This section includes the following topics:
About Fibre Channel Write Acceleration
The Fibre Channel write acceleration feature also allows the configuration of the buffer count. You can
change the number of 2-KB buffers reserved on the target side DPP for a SCSI flow.
You can estimate the number of buffers to configure using the following formula:
(Number of concurrent SCSI writes * size of SCSI writes in bytes) / FCP data frame size in bytes
For example, HDS TrueCopy between HDS 9970s uses 1-KB FCP data frames. You perform an initial
sync for a 16-LUN TrueCopy group with 15 tracks, or 768-KB per LUN, requires approximately
16*(768*1024)/1024 or 12248 write buffers.
The Fibre Channel write acceleration feature requires the Enterprise Package license installed on both
the initiator and target switches.
OL-16184-01, Cisco MDS SAN-OS Release 3.x
Fibre Channel Write Acceleration, page 48-1
Displaying Fibre Channel Write Acceleration Information, page 48-2
Default Settings, page 48-4
About Fibre Channel Write Acceleration, page 48-1
Enabling Fibre Channel Write Acceleration, page 48-2
C H A P T E R
Cisco MDS 9000 Family CLI Configuration Guide