Cisco Cisco MDS 9000 XRC Acceleration White Paper
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WHITE PAPER
FIBRE CHANNEL WRITE ACCELERATION
The Cisco
®
MDS 9000 Family of Multilayer Directors and Fabric Switches provide a complete set of intelligent storage services
that include Fibre Channel Write Acceleration (FC-WA), which can dramatically improve the number of Small Computer
System Interface (SCSI) I/O operations per second over long-distance in a Fibre Channel-based storage area network (SAN),
by reducing the effect of transport latency on the processing of each operation.
SUMMARY
Modern data centers are built around SANs that provide secure, reliable, and scalable centralized data-storage facilities. An effective business-
continuance and disaster-recovery plan mandates the deployment of multiple data centers located at optimal distances to protect against regional
power failures or disasters, yet close enough for synchronous data replication without affecting the application performance. Achieving this
balance for successful business continuance poses a significant challenge for businesses.
continuance and disaster-recovery plan mandates the deployment of multiple data centers located at optimal distances to protect against regional
power failures or disasters, yet close enough for synchronous data replication without affecting the application performance. Achieving this
balance for successful business continuance poses a significant challenge for businesses.
The time in which the business needs to recover during a disaster determines the type of data replication required. Synchronous data replication
provides the least amount of downtime but requires the data centers to be close enough so that the application performance is not affected by the
latencies introduced for every I/O operation. Asynchronous or semi-synchronous replication allows for greater distance but the data centers are in
lock step with each other, with the secondary data center lagging behind the primary by a fixed amount of time. This in turn implies that there is a
loss of data for that period of time. An optimal solution is to increase the distance between the data centers without introducing additional latency for
I/O operations.
provides the least amount of downtime but requires the data centers to be close enough so that the application performance is not affected by the
latencies introduced for every I/O operation. Asynchronous or semi-synchronous replication allows for greater distance but the data centers are in
lock step with each other, with the secondary data center lagging behind the primary by a fixed amount of time. This in turn implies that there is a
loss of data for that period of time. An optimal solution is to increase the distance between the data centers without introducing additional latency for
I/O operations.
The Cisco MDS 9000 Family provides FC-WA, capable of dramatically reducing the effect of transport latency during the time needed to complete
an SCSI operation over distance. Consequently FC-WA allows longer-distance between the primary and secondary data centers, increasing the
resilience of the solution and the flexibility in selecting the locations with the least impact on the application performances, and improving
application performance for a given configuration.
an SCSI operation over distance. Consequently FC-WA allows longer-distance between the primary and secondary data centers, increasing the
resilience of the solution and the flexibility in selecting the locations with the least impact on the application performances, and improving
application performance for a given configuration.
The FC-WA feature is supported on the Cisco MDS 9000 Family Storage Services Module, and may be used on any Cisco MDS 9200 Series of
Multilayer Fabric Switches and Cisco MDS 9500 Series of Multilayer Directors running the Cisco SAN-OS Release 2.0(2b) or later, with the
Enterprise Licensing package.
Multilayer Fabric Switches and Cisco MDS 9500 Series of Multilayer Directors running the Cisco SAN-OS Release 2.0(2b) or later, with the
Enterprise Licensing package.
CHALLENGE
The term “business continuity” implies the availability of the entire set of physical, logical, and human resources needed to run the business in the
event of an unforeseen stoppage. The physical infrastructure includes the location and its associated resources, with respect to the IT area; these
resources include the physical servers, storage, and network equipment. The logical infrastructure is the data or information needed to continue with
the business. It is imperative that a finite set of procedures and processes be put in place along with the adequate technology to maintain business
continuity.
event of an unforeseen stoppage. The physical infrastructure includes the location and its associated resources, with respect to the IT area; these
resources include the physical servers, storage, and network equipment. The logical infrastructure is the data or information needed to continue with
the business. It is imperative that a finite set of procedures and processes be put in place along with the adequate technology to maintain business
continuity.