Белая книга для Cisco Cisco MDS 9000 I O Accelerator
Deployment Guide
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Cisco I/O Accelerator Deployment Guide
Introduction
This document provides design and configuration guidance for deploying the Cisco
®
MDS 9000 Family I/O
Accelerator (IOA) feature, which significantly improves the performance of the SAN Extension solution to meet
business continuity and disaster recovery requirements. Cisco IOA is a transport- and speed-agnostic traffic
acceleration service capable of mitigating the effects of distance (and hence latency) on application throughput,
thereby bringing flexibility to the choice of the data center location. This document focuses on deployment of disk-
replication and tape-backup solutions using Cisco IOA, which are the most common applications for a SAN
Extension solution.
Business Continuity and Disaster Recovery Requirements
A SAN Extension solution for business continuity and disaster recovery requires features and capabilities that
provide flexibility and robustness to the deployment. Traffic acceleration and optimization services are needed to
help to build a highly available and scalable business continuity and disaster recovery solution. This section
discusses each of these requirements in detail and describes the way that Cisco IOA helps address these
requirements.
Flexibility in Selecting the Data Center Location
An ideal business continuity and disaster recovery plan mandates the deployment of multiple data centers located at
optimal distances and locations to protect against regional power failures or disasters, yet close enough for data
replication without affecting the application performance. In many cases, the primary data center replicates data to a
relatively nearby secondary data center over a metropolitan area network (MAN), and the secondary site in turn
backs up the data to a more distant disaster recovery site across a WAN. This approach provides a good balance of
recovery point objective (RPO) and recovery time objective (RTO) values for all levels of outage, but depending on
the location, such a model can be costly. The challenge is to optimize the cost by finding the right data center
locations for business continuity and disaster recovery. The main bottleneck for replication and backup between the
data centers is the distance between them. Data center interconnect (DCI) distance adds to the latency of the link.
By reducing the latency of the I/O exchanges between the replication node and the secondary storage location,
Cisco IOA extends distances for replication. This extension provides flexibility in selecting the locations while
reducing the effect on application performance. The actual effective distance depends on the application
requirements and the infrastructure.
Reduced Tape Backup Windows
Electronic data vaults using virtual or physical tape backup applications have become an integral part of an
enterprise’s business continuity and disaster recovery plan. However, uninterrupted and timely completion of the
backup jobs is critical to meet stringent service-level agreements (SLAs), which include ever-smaller backup
windows.
Cisco IOA accelerates tape read and write I/O between the backup applications and virtual or physical tape libraries,
which not only reduces the backup windows but also enables remote tape vaulting over extended distances without
degrading application performance. Remote tape vaulting gives customers the flexibility to locate their tape backup
data centers remotely and to back up and restore data in real time without having to manually ship tapes to remote
locations.