There are three approaches to data replication in the Client-Server environment and focusing on the SMB (small to medium size business) market;

·         Host based

·         Array (storage device) based

·         Network (appliance) based (a blend of hardware and software)

Before investing in each, and organization must perform some type of Business Impact Analysis (BIA))to determine cost justification. Consider two scenarios;

·         Bank or organizations with large amounts of in-flight transactions would need real-time replication (low DRO- see section 4.7.1) if the cost of losing the data justifies the cost to implement the technology (Typically $30K+ leased line)

·         A medical office enters Exam data into a Electronic Medical Record system (EMR) that averages 20 exams per hour, would only loose 2 exams with a RTO of 5 minutes for a typical Array based storage system ($10K). Host based, at a cost of $500 per server, would be more cost effective.

This document will review existing technologies related to data replication in the industry and provide insight on recommended uses and applications.  A comparison of selected products will be used to demonstrate technology application.