Monitoring an N-Tier Environment

A typical n-tier environment consists of three layers:

• The presentation tier is the layer which provides the user interface, such as a web browser or a fat client application.
• The middle tier, also referred to as the business logic tier, is made up of components such as MSMQ (Microsoft Message Queue) messages, MTS (Microsoft Transaction Server), or COM+ applications, and ASP (Active Server Pages) for content.
• The third tier is the data tier and consists of the database, stored procedures, and components for data processing.
  
  Why Monitor?
  
  Any mission critical website needs to employ some type of monitoring. An article entitled "Diagnostic Hooks"' from Microsoft encourages active monitoring.

"The best monitoring solution is to use application management suites from third-party vendors that monitor the hardware, network, and software simultaneously. These packages are able to monitor for errors and then respond with automatic notifications via e-mail, pager, or other sophisticated methods." ...

The Presentation Tier

The user interface is a key area for monitoring. You want to find any problems before they reach the end user, giving the impression that your website is functioning flawlessly. Start by finding out what critical functionality the user performs on your site. Set up monitors to log in to the site and to access critical pages. Use Cuevision Server Monitor to send alerts to the network administrator if response is too slow, if the page does not return a successful 200 code, or if the content doesn't match.

The Middle Tier

You can accomplish critical services, such as the message queue service, IIS (Internet Information Server), and MSDTC (Microsoft® Distributed Transaction Coordinator), with the service watch type in Cuevision Server Monitor. You can receive a notification email, as well as implement a recovery action to restart the service. Other opportunities for monitoring include watching any partner websites that your middle tier servers communicate with.

The Data Tier

Monitoring the database servers can start with a physical check; that is, you can use the ping watch type to see if the server is communicating on the network. Monitor the database service with the service watch. Use a custom watch type to issue an SQL (structured query language) query.