Increasing Availability for BizTalk Server

How you can increase the availability of your BizTalk Server system?

I have been asked this question before, first think that comes to my mind is that you can easily redundant the servers which hosts your BizTalk application this was good answer at this time but after that i decide to know more about this i read too many articles concerning this issue plus disaster recovery and it ends up to the following .

there are many strategies you can follow to reach high availability but first lets explain the difference between high availability and disaster recovery.

Disaster recovery allows you to resume operation of a failed system but is typically a manual process and requires more recovery time than a high-availability implementation. Therefore, a disaster recovery implementation provides availability but not high availability. You should employ both high availability through server clusters and load balancing, and availability through disaster recovery, in a production BizTalk Server environment.

Now what are the strategies for high availability of your BizTalk application:

• Providing high availability using Windows Clustering. A server cluster is a group of independent computer systems, known as nodes, working together as a single system to ensure that critical applications and resources remain available to clients. If one of the nodes becomes unavailable as a result of failure or maintenance, another node immediately begins providing service (a process known as failover).
• A server cluster is typically recommended for the computers running SQL Server that house the BizTalk Server databases.
• A server cluster may be required to provide high availability for certain BizTalk adapters.
• A server cluster is typically recommended for the Enterprise Single SignOn master secret server.
• Providing high availability using Network Load Balancing (NLB). NLB delivers high availability by redirecting incoming network traffic to working cluster hosts if a host fails or is offline. Unlike server clusters, NLB does not require special hardware.NLB is provided for BizTalk Hosts by adding multiple servers to a group.Load balancing is provided for SQL Server disks through the use of a SAN or by adding multiple MessageBox databases.
• Increasing availability using BizTalk Server log shipping and disaster recovery.
• Increasing availability through implementation of the appropriate monitoring and maintenance strategies.