1.2 Enterprise Replication Enterprise Replication (ER) provides the ability to replicate data to and from multiple database systems. It has rich functionality, supporting full row replication, selective replication, update anywhere, and conflict resolution. We can replicate part of a table to multiple nodes where some rows go to some targets and other nodes can go to another target. We often refer to all of the servers acting as a source or target of ER as being a member of the ER domain. Each server in the ER domain is an independent server, which is different than the secondary nodes of the MACH11 cluster. Each server can have data that is local to that server as well as data that is common across the ER domain. Additionally, each node within the ER domain can be a MACH11 cluster. This means that is possible to have a cluster of clusters with near limitless scale-out. The rich feature set of ER does come with a price. Administration can be a bit daunting. Informix has reduced the complexity over the years by introducing such functionality as templates, and has reduced the administrative requirements even further with the Flexible Grid. 1.3 The Flexible Grid The Flexible Grid allows us to have multiple servers on which everything is replicated, not just the data changes made to tables. Inserts, updates, and deletions are replicated, but so are statements such as "create database...", "create table...", "create index....", "create procedure...", "grant...". Because data definition language (DDL) statements are replicated as well as data manipulation language (DML), each of the nodes within the Flexible Grid can be fully used as an independent server, providing for near limitless scale-out. The Flexible Grid may be built on ER, but only requires a small subset of the ER administration, that is, the ER commands to define how the servers are connected to each other to perform propagation. You do not have to define what is to be replicated or where it is to be replicated. You simply issue the "create table..." statement, and that table is created on all nodes within the Flexible Grid and data synchronization is automatically established. You can dynamically add nodes to the Flexible Grid based on business requirements. Perhaps you must add a new node to provide additional resources for a new website. You can use the ifxclone utility to add the new node. After cloning, the new node is automatically included as a member of the Flexible Grid. Chapter 1. Overview 5