Some things to keep in mind when it comes to Web Application Watcher nodes…

1.       It can take upwards of 15 minutes for the URL MPs to be downloaded to the Watchers and to get them reporting back to the Mgt servers

a.       You will not see any information in the Web Application State view until the URLs are reporting back. You would think you would see the Web Application in the state view as Not Monitored, but you don’t. Until they have been pushed to the Watchers and are reporting back a good or bad state the Web Application state is blank.

2.       Once you uninstall the agent from the “watcher” you cannot access Performance data about the URLs that the watcher was monitoring. I’m looking to see what kind of SQL query can be written to find and extract the data from the DB or the DW.

3.       By default a web application runs once every 60 seconds. You can of course change that when you are creating it, however the lowest you can set this number is 30 seconds. You can edit the XML to a lower number, but that causes problems with the URL and watcher making the data less reliable, so we don’t recommend doing that. And honestly if you are running queries that often there is a chance (depending on the number of Web Apps you are creating) of overloading the Watchers.

4.       Depending on how frequent you run them and how many web applications you are monitoring Watchers can get over loaded and will exhibit this in a variety of ways.

a.       There’s the obvious performance issues (over loaded procs, high memory usage).

b.      You may also see frequent agent failovers, as the GWs or Mgt Servers your watcher and standard agents report to are too busy and become over whelmed.

c.       You may see a high send queue alert from the Watchers, this would be a sign that the watchers are too busy to keep up with the amount of data they are trying to send (don’t forget they are also processing their own OS and HW data).

d.      It’s a good idea if you are going to monitor a lot of URLs (a lot meaning 100+) to spread them over a number of watchers. Dedicated Watchers make great VM candidates.

While MOM 2005 wasn’t the best product for URL monitoring in the past, SCOM 2007 has come a long way and with the right tuning and architecture you can use it to monitor large complex environments and give products like SiteScope a run for its money.