High availability for BizTalk Server 2006 focuses on recovering functional components that might disrupt availability in a BizTalk Server deployment.

To demonstrate high availability in BizTalk Server 2006, you have to apply failure and measure the product's effectiveness in recovery. A highly available BizTalk Server deployment makes errors and failures transparent to external applications and systems, and makes sure that all services continue functioning correctly with minimal disruption.

Designing a BizTalk Server 2006 deployment that provides high availability involves implementing redundancy for each functional component involved in an application integration or business process integration scenario. BizTalk Server 2006 simplifies the implementation of these scenarios by conceptually separating the data from the hosts that process the data. So providing high availability for BizTalk Server 2006 involves running multiple host instances and clustering the BizTalk Server databases, as follows:

• Architecture for BizTalk Hosts. BizTalk Server 2006 lets you separate hosts and run multiple host instances to provide high availability for key functions such as receiving messages, processing orchestrations, and sending messages. These hosts do not require any additional clustering or load-balancing mechanism because BizTalk Server 2006 automatically distributes workload across multiple computers through host instances. However, hosts running the receive handler for the HTTP, SOAP, and BizTalk Message Queuing (MSMQT) adapters require a load-balancing mechanism such as Network Load Balancing (NLB) to provide high availability.
  
  
• Architecture for BizTalk Server databases. High availability for the BizTalk Server 2006 databases typically consists of two or more database computers configured in an active/passive server cluster configuration. These computers share a common disk resource (such as a RAID5 SCSI disk array or storage area network) and use Windows Clustering to provide backup redundancy and fault tolerance.
  
  

Note
Highly-available environments are, by nature, multi-computer environments. When configuring BizTalk Server 2006 in a multi-computer environment you must use domain user groups and accounts.

This document provides information about how to address high availability in each of these categories. Because BizTalk Server 2006 is built on Microsoft Windows Server™ 2003 (or Windows® 2000 Server) and Microsoft SQL Server™ 2000 or 2005, make sure that you deploy these products with high availability before configuring hosts for BizTalk Server 2006. The following links include information about providing high availability for these underlying products:

• Chapter 15 - High Availability Options, SQL Server Resource Kit, available at http://go.microsoft.com/fwlink/?LinkId=24431.
  
  The Microsoft SQL Server Resource Kit covers many administrative and deployment planning areas. Chapter 15 covers planning for fault tolerance and recovery.
  
  
• Microsoft Windows Server 2003 Deployment Kit, available at http://go.microsoft.com/fwlink/?LinkId=24432.
  
  The Microsoft Windows Server 2003 Deployment Kit provides guidelines and recommended processes for designing and deploying Windows Server 2003 technologies.
  
  
• Windows Server 2003 Deployment Kit: Planning Server Deployments, available at http://go.microsoft.com/fwlink/?LinkId=24433.
  
  This book provides information about planning server storage, and information about designing and deploying file servers, print servers, and terminal servers in medium and large organizations.
  
  

• Providing High Availability for BizTalk Hosts
  
  
• Providing High Availability for BizTalk Server Databases
  
  

Concepts