Data Replication

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Data Replication

Data replication generates and manages multiple copies of data at one or more sites, which allows an enterprise to share corporate data throughout its organization. Data replication provides a backup system in case of a catastrophic failure.

High-Availability Data Replication

High-Availability Data Replication (HDR) provides synchronous data replication for Dynamic Server. HDR allows you to replicate database data running simultaneously on a second computer. If one site experiences a disaster, you can immediately direct applications to use the second database server in the data-replication pair.

For information about HDR, see the IBM Informix Administrator's Guide.

HDR can be combined with Enterprise Replication. For more information, see the IBM Informix Dynamic Server Enterprise Replication Guide.

Enterprise Replication

Enterprise Replication captures transactions to be replicated throughout the enterprise. On the source database server, Enterprise Replication reads the logical log and transmits each transaction to the target database servers. At each target database server, Enterprise Replication receives and applies each transaction to the appropriate databases and tables. Enterprise Replication can be combined with HDR.

For more information, see the IBM Informix Dynamic Server Enterprise Replication Guide.

Types of Data That You Can Replicate

Table 2 shows the types of data that you can replicate with HDR or Enterprise Replication.

Table 2. Data Types that HDR and ER Replicate
Data Type	HDR Support	ER Support
Atomic data types such as numeric, character, varying character, time, Boolean	Yes	Yes
Simple large objects in dbspaces	Yes	Yes
Simple large objects in blobspaces	No	Yes
User-defined data types	Yes	Yes ¹
DataBlade types (text, image, video, web, and geodetic)	Yes	Yes
Smart large objects	Yes	Yes ²
Notes: 1. To replicate user-defined data types, the required streamwrite() and streamread() functions must exist. For information on writing and registering support functions, see the section on writing Enterprise Replication stream support functions in the IBM Informix DataBlade API Programmer's Guide. 2. For information on restrictions for replicating smart large objects, see the IBM Informix Dynamic Server Enterprise Replication Guide.