This document discusses concepts around implementing BizTalk Server 2006 in a highly available environment. It defines high availability as eliminating single points of failure through redundancy of functional components. The main BizTalk components discussed are databases, services (host instances), and adapters. For databases, it recommends using a SQL Server cluster in active/passive mode. For hosts and adapters, it recommends scaling out across multiple servers using multiple host instances, and in some cases load balancing technologies like Network Load Balancing. It provides guidance on high availability configurations for receiving, processing, and sending hosts.

1. Highly Available BizTalk
Concepts Around the Implementation of
BizTalk Server 2006 in a High Availability Environment
Daniel Toomey & Patrick Hood
presenters

2. Goal of This Presentation
 Not highly technical (i.e. no code)
 Not demo-heavy
 Discussion of the main concepts and strategy
of HA in an integration solution
 Understand Microsoft recommended
practices

3. Definition of High Availability (HA)
“…is a system design protocol and associated
implementation that ensures a certain
absolute degree of operational continuity
during a given measurement period.”
(www.wikipedia.org/wiki/High_Availability)

4. Definition of High Availability (HA)
 Redundancy of each functional component
 Seeks to eliminate “single point of failure”
 Single component failure triggers recovery
mechanisms that are transparent to users of
the system

5. High Availability vs High Performance
 High Availability is about Failover
 Does not necessarily involve load balancing
 Active/Passive configuration
 Scaling Out
 High Performance is about… Performance!!
 Typically about load balancing and managing
high throughput
 Active/Active configuration
 Scaling Out or Scaling Up
 Not necessarily Highly Available

6. High Availability and Integration
?

7. High Availability in BizTalk
 BizTalk Components
 Databases (SQL Server)
 Services (Host Instances)
 Adapters (Send / Receive)
 Enterprise Single Sign-On (SSO)
 Process for ensuring High Availability is
different for each of these components

8. BizTalk Groups
 Out-of-the-box functionality for BizTalk allows
for the easy (and default) establishment of
“BizTalk Groups”
 A BizTalk Group is a collection of servers that
host BizTalk services (hosts) which operate
upon the same Message Box(es)
 All hosts within a BizTalk Server Group are
based upon the same set of configuration and
message storage databases
 Automatic Load Balancing

9. HA for BizTalk Databases
 SQL Server supports BizTalk through data
persistence:
 Stores all configuration, business rules, message state
and tracking info
 Stores the messages themselves
 Separates data from hosts that process the data
 The most critical component in a BizTalk architecture
 Can be implemented as a SQL Server Cluster
(active / passive mode)

10. HA for BizTalk Databases

11. HA for BizTalk Databases
1. Create global domain accounts
2. Configure the SQL Server cluster before
BizTalk installation
3. Install BizTalk
4. Run the BizTalk Configuration Wizard in
custom configuration mode
5. Specify the SQL Server cluster for the
BizTalk databases

12. HA for BizTalk Databases
 Failover Behaviour in BizTalk:
 BizTalk databases are temporarily unavailable during
failover
 In-process host instances are recycled until connection
to the SQL Server is automatically restored
 Isolated host instances are paused, an error is
generated in the BizTalk Server 2006 Application log
and receive locations are disabled
 Once connection to the SQL databases is restored,
document processing resumes normally and receive
locations are enabled

13. HA for BizTalk Databases
 SQL Server Database Mirroring
 Not currently a supported solution for ensuring
high availability of the Microsoft BizTalk
Server 2006 databases
 Potential problems maintaining transactional
consistency in the BizTalk databases
 Log Shipping is the recommended practice for
Disaster Recovery

14. HA for BizTalk Hosts
 Hosts provide logical containers for
functionality:
 Receiving
 Sending
 Processing
 Recommended practice is to create hosts for
each separate functionality
 Creates security boundaries
 Easier management & scalability

15. HA for BizTalk Hosts
 In-process Hosts
 Run inside of BizTalk runtime process
 Contain all non-Web-based artefacts:
 Orchestrations
 Adapter send handlers
 Adaptor receive handlers
(except for HTTP & SOAP)
 Isolated Hosts
 Do not run inside of BizTalk runtime process
 HTTP and SOAP receive handlers

16. HA for BizTalk Hosts
 BizTalk Server 2006 lets you separate hosts and run
multiple host instances to provide high availability
 No additional clustering or load-balancing mechanism
required because BizTalk Server 2006 automatically
distributes workload across multiple computers
through host instances
 However, hosts running the receive handler for the
following adapters require a load-balancing
mechanism such as Network Load Balancing (NLB)
to provide high availability:
 HTTP
 SOAP
 BizTalk Message Queuing (MSMQT)

17. HA for BizTalk Hosts (Receiving)
 Scaled Out Receiving Hosts

18. HA for BizTalk Hosts (Receiving)
 Scaled Out Receiving Hosts (multiple clients)

19. HA for BizTalk Hosts (Receiving)
 Using host instances on multiple computers:
 FILE Adapter (point host instances to same UNC path)
 SQL Adapter (point host instances to same database table)
 Using host instances on multiple computers with NLB:
 HTTP Adapter (subscribe to a shared clustered URL)
 Web Services Adapter (NLB distributes incoming messages)
 SharePoint Adapter (subscribe to a shared URL)
 MSMQT Adapter (NLB distributes incoming messages)
 Using a clustered BizTalk host (req. Enterprise Edition):
 FTP Adapter
 POP3 Adapter (multiple concurrent connections)
 MSMQ Adapter

20. HA for BizTalk Hosts (Receiving)
Adapter Type Default Config NLB Cluster Clustered Host
FILE

HTTP

SOAP

SQL

WSS

FTP

POP3

MSMQ


21. HA for BizTalk Hosts (Processing)
 Scaled Out Processing Hosts

22. HA for BizTalk Hosts (Processing)
 Scaled Out Processing Hosts
 Orchestration state is maintained centrally
in SQL Server, not locally on each BizTalk
Server computer
 BizTalk load balances automatically
 One instance can complete a process
started by another instance
 Proof – of – Concept

23. BizTalk Host Load Balancing
 Used “CallOrchestration” sample from SDK
 Inserted Delay shapes and trace messages to
log the step and the processing server
 Deployed to two servers in a BizTalk Group
 Submitted 1000 files
 Analysed the resulting logs
For more than 25% of the files, processing
steps were divided across more than one
individual server (i.e. host instance)

24. HA for BizTalk Hosts (Sending)
 Scaled Out Sending Hosts

25. HA for BizTalk Hosts (Sending)
 Scaling Out Sending Hosts
 Similar to Processing Hosts – Host & Data Independence
 Special Considerations:
 FTP Send Adapter
 Run in a clustered BizTalk Host
 Supports only one host instance running at a time
 MSMQ Adapter
 Cluster the MSMQ Service
 Cluster the BizTalk Host in the same group
 Configure MSMQ Send Handler within clustered host

26. BizTalk Host Clustering
 Only necessary for certain adapters
 Requires BizTalk 2006 Enterprise Edition
 Requires BizTalk Servers to be configured as a Windows
Server Cluster first
 Considerations:
 Non-clustered host should not be run on a Windows Server
cluster where Enterprise SSO is clustered
 More info:
 http://msdn2.microsoft.com/en-us/library/aa560059.aspx

27. Network Load Balancing (NLB)
 As previously mentioned, the following adapters
require a load-balancing mechanism such as
Network Load Balancing (NLB) to provide high
availability:
 HTTP
 SOAP
 BizTalk Message Queuing (MSMQT)
 Can load-balance the BAM portal & BAS website
 Provides High Availability at the Network level, rather
than the Resource level

28. Network Load Balancing (NLB)
 NLB farm of servers appears as one server to
clients
 Distributes load between the servers in the
farm
 Each server in the NLB farm is aware of each
other and automatically handle server
unavailability
 Each server is fully self-contained
 BizTalk grouping provides balancing on
hydration of long-running processes

29. Network Load Balancing (NLB)

30. Network Load Balancing (NLB)
 Easier and more flexible management
 Rolling OS update & software deployment
 Uninterrupted availability and fault tolerance
 Server failure & hardware update/replacement
 Better scalability
 True horizontal scalability
 Up to 32 servers in an NLB farm
 Multiple farms via DNS round-robin

31. Network Load Balancing (NLB)
 Option of Hardware-based or Software-based
NLB solution
 Hardware-based solution consists of a
specialised network appliance e.g.
 F5 Networks
 Radware
 Cisco
 Foundary
 Alteon

32. Windows NLB
 Full software NLB implementation
 Supported on all versions of Windows
2003 Server
 Supported on Windows 2000 Advanced
Server and Datacenter Server Editions
 Generally a 5-10% overhead per server
 MSCS and Windows Network Load
Balancing (NLB) are NOT supported on
the same set of nodes

33. Windows NLB
 Consider NICs & Unicast vs. Multicast
Mode & Number of NICs Use
Single network adapter in unicast mode A cluster in which ordinary network communication
among cluster hosts is not required and in which there
is limited dedicated traffic from outside the cluster
subnet to specific cluster hosts.
Multiple network adapters in unicast mode A cluster in which ordinary network communication
among cluster hosts is necessary or desirable. It is also
appropriate when you want to separate the traffic used
to manage the cluster from the traffic occurring
between the cluster and client computers.
Single network adapter in multicast mode A cluster in which ordinary network communication
among cluster hosts is necessary or desirable but in
which there is limited dedicated traffic from outside the
cluster subnet to specific cluster hosts.
Multiple network adapters in multicast mode A cluster in which ordinary network communication
among cluster hosts is necessary and in which there is
heavy dedicated traffic from outside the cluster subnet
to specific cluster hosts.

34. Windows NLB
 Port-rules – multiple-host or single-host
 Affinity - can be set to:
 None
 Single-client (or sticky-IP)
 Class C
 Host Priorities
 For BizTalk NLB, recommend multiple
host, no affinity, even priority

35. Enterprise Single Sign-On (SSO)
 Critical part of the BizTalk infrastructure
 Helps to secure information for the receive
locations
 Master Secret Server
 Stores the encryption key used to secure data
in the credentials database
 Must configure the first computer where SSO
is installed as the Master Secret Server

36. Enterprise Single Sign-On (SSO)
 If Master Secret Server fails, currently running
operations continue but cannot encrypt new
credentials
 BizTalk Server dependency on Master Secret
Server:

37. High Availability for Ent SSO
 Master Secret Server CANNOT exist on an
NLB cluster
 Master Secret Server can be moved from
BizTalk NLB servers (often to SQL Server
infrastructure)
 Master Secret Server can be clustered

38. Summary
 In an multi-system environment, High Availability
means securing not only the individual systems
themselves but also the integration architecture
 BizTalk Server 2006 can be implemented to support
High Availability using a variety of techniques and
configurations for the various components:
 OTB functionality via BizTalk Server Groups
 SQL Server Failover Cluster
 Windows NLB Cluster
 Clustered Hosts

39. References
 Planning for High Availability
http://msdn2.microsoft.com/en-us/library/aa558765.aspx
 Planning Your Platform for Fault Tolerance
http://msdn2.microsoft.com/en-us/library/aa560135.aspx
 Creating a Highly Available BizTalk Server Environment
http://msdn2.microsoft.com/en-us/library/aa560847.aspx
 Sample BizTalk Server High-Availability Scenarios
http://msdn2.microsoft.com/en-us/library/aa578057.aspx
 Providing High Availability for BizTalk Server Databases
http://msdn2.microsoft.com/en-us/library/aa559920.aspx
 High Availability for Enterprise Single Sign-On
http://msdn2.microsoft.com/en-us/library/aa560674.aspx
 High Availability for the BizTalk Base EDI Adapter
http://msdn2.microsoft.com/en-us/library/aa561569.aspx
 High Availability and the Microsoft Operations Framework
http://msdn2.microsoft.com/en-us/library/aa560207.aspx
 Using Windows Server Cluster to Provide High Availability for BizTalk Hosts
http://msdn2.microsoft.com/en-us/library/aa560059.aspx

40. Questions?