Introduction

Few Problems

• BizTalk is performing slower ,when we drop the messages or during high volume of messages
• Large no of messages are causing memory errors in BizTalk farm
• Prolonged BizTalk Throttling
• BizTalk receive location is not picking up the files
• BizTalk Database Jobs are taking too much time to complete
• Response time of message processing is increasing. There is a high latency in environment
• It seems BizTalk is not able to process any message, The messages or service instance are in Active/Running State, however nothing is happening
• SOAP Adapter is taking long time call a Web Service
• Orchestration/Receive Port is taking  long time to debatch a large message
• BizTalk production farm has suddenly started behaving strangle

Few Requirements

• Looking for creating scalable BizTalk solutions
• Looking to achieve a particular latency for a BizTalk application
• Requirement to process 1000 messages in 1 seceond by BizTalk application
• Requirement of processing large messages in BizTalk Server
• Planning to change the performance throughput
• Trying to determine/test maximum sustainable throughput ( MST ) of my BizTalk farm
• Trying to figure if BizTalk farm can support next 20+ applications which are in pipeline
• How should I decide if My BizTalk farm needs to be tuned or optimized
• How  should I decide if BizTalk production farm needs to be scaled up

What Should We Do Now!

First Few Things

If  you have anything similar in the list above (Few Problems), Then you should start with doing below things

• SQL Server Agent and BizTalk Server Jobs Status on your BizTalk SQL Server Instance - The agent should always be running and all the BizTalk Jobs should be enabled from the day one in your production Farm , If there are any issues refer this in-depth wiki , "BizTalk Server:Databases: Survival Guide"
• The Biztalk Host instance that has the "allow Host tracking" option set is stopped - If the host is stopped , then it should be started without any delay. As a practice there should always one dedicted "Tracking Host" should be running in BizTalk Farm.

Review Application Design

Start reviewing the application design and architecture. Sometime a design change may have huge impact over the application performance. Following should be the starting reference points while reviewing the design and code of BizTalk solutions

• Code of Custom Pipeline component
• Are we using XMLDom to load the messages in pipeline
• What is the method used to read the values in incoming message , Use streaming while reading the message or use XpathReader
• Code of Orchestration
• Design of MAP used in transformation of large messages
• Are we using Enterprise Integration Patterns or not while designing solutions
• What kind of Custom Code we are using?
• Can we use inline send port instead of normal send ports?
• How we are calling Business Rule engine in our BizTalk Orchestrations?
• How many scopes have been used in orchestration

Reference for Code Review/Solution Design

• Optimizing Pipeline Performance
• Optimizing Memory Usage with Streaming
• FAQ for BizTalk Orchestrations
• BizTalk Orchestration Profiler

Review Everything Else!

MSDN

• How BizTalk Server Implements Host Throttling - Refer this about getting familiar with Throttling concepts and how the BizTalk Engine does it. 
• What is Host Throttling - Refer this about details of Host Throttling
• Microsoft BizTalk Server Automatic Throttling (Wiki) - In-depth details about throttling
• Throttling - MSDN Blog - Provides details about throttling and how to use performance counters to know more about it.
• Host Throttling Performance Counters - Provides the performance monitor counters that measure system parameters that impact host throttling
• Measuring Maximum Sustainable Engine Throughput-  Refer this for more details about MST and Testing aproaches to determine MST of your BizTalk Engine.
• Load Pattern Tests to Determine Maximum Sustainable Throughput- Refer this about using Visual studio to perfrom automated testing to figure MST
• Measuring Maximum Sustainable Tracking Throughput - Refer this to know more about MST of BizTalk DTA Tracking throughput
• Processing Large Messages - The article defines large messages and provides guidelines for how to configure BizTalk Server process large messages efficiently

Blogs

• Identify Performance Bottlenecks in your BizTalk Environment – Part I
• Identify Performance Bottlenecks in your BizTalk Environment – Part II
• Threads Dsatabase Sessions and Throttling 
• Throttling in Full Action - By Yossi Dahan
• BizTalk Orchestration Throttling Pattern- By Richard Seroter
• Configure BizTalk hosts per Application- By Thiago Almeida
• Host Tracking and the BizTalk MessageBox- By Nick Heppleston
• Orchestration Performance Webcast - By Alan Smith

Hot Fixes

• KB2627804 - Hotfix that improves the performance of the tracking feature in BizTalk Server