Cisco Cisco Data Mobility Manager Folheto

Solution Overview

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Cisco MDS 9000 Family Acceleration Services: Enhance
Synchronous Replication Performance

What You Will Learn

A comprehensive business continuity and disaster recovery (BC/DR) plan mandates the deployment of multiple data

centers located far enough apart to protect against regional power failures or disasters, yet close enough together

for synchronous data replication without affecting application performance. Synchronous replication solutions such

as EMC Symmetrix Remote Data Facility/Synchronous (SRDF/S) and Hitachi TrueCopy Synchronous provide a

continuous, nondisruptive, host-independent remote data replication solution for disaster recovery or data migration

over distance. However, application performance is affected by the distance and latency between the data centers,

which restricts the location of the data centers.

The biggest challenge for synchronous replication is its distance limitation. Fibre Channel, the primary enterprise

storage transport protocol, is limited only by its physical-layer flow-control mechanism. However, latency becomes a

problem because propagation delays lengthen with increased distance. Propagation delays can significantly slow

down a system by forcing it to wait for confirmation of the completion of each storage operation at both the local and

remote sites. This means that the practical distance for synchronous replication is about 100 to 200 km, or 60 to 120

miles, depending on the application response time tolerance and other factors.

Cisco

MDS 9000 Family switches offer traffic acceleration services capable of dramatically reducing I/O latency

between data centers and thereby increasing the distance for synchronous replication solutions. Cisco MDS 9000

I/O Accelerator (IOA) offers industry-leading, highly resilient, clustered, and transport-independent architecture for

both Fibre Channel and Fibre Channel over IP (FCIP) transports, providing the best I/O acceleration service in the

industry.

This document describes tests that demonstrate that Cisco MDS 9000 IOA enhances synchronous replication

performance and extends replication distance between primary and secondary data centers.

Challenge

Today’s businesses operate more than one data center at different locations as part of a BC/DR plan. Such a model

helps optimize the cost of running data centers while complying with government regulations. An effective BC/DR

plan mandates the deployment of multiple data centers located far enough apart to protect against regional power

failures or disasters, yet close enough together for synchronous data replication without affecting application

performance. Achieving this balance for successful business continuance poses a significant challenge for

businesses.

Synchronous replication solutions provide remote replication for BC/DR. Replication can be either storage-array

based or host based. EMC SRDF/S and Hitachi TrueCopy Synchronous are examples of array-based replication

solutions.

The recovery point objective (RPO)—the amount of data loss during a failure—and recovery time objective (RTO)—

the amount of time that the business needs to recover after a disaster—determines the type of replication deployed.

Synchronous data replication provides the best RPO but requires the data centers to be located close enough to

maintain consistent application performance.