Application Restart: What is it?

[James Hunter Ross]

Friends,

We have been experiencing unexpected Application Timeout issues in our ASP
1.1 application. We eventually read-up on aspnet_wp (or w3wp) "recycling"
and various related concepts configuration settings. I did a post here
Thursday and a response from "JIMCO Software" gave us clues about
"Application Restarts" and an associated PerfMon counter we could use to
monitor restarts.

After watching the PerfMon counter, it turns out that sometimes our
application is restarted. (This is not logged event viewer, but the PerfMon
counter is incremented.) Apparently we were wrong to be focusing on
aspnet_wp (or w3wp) "recycling".

So what is an Application Restart, and why might it be happening
unexpectedly?

Any thoughts or words will be greatly appreciated. Thanks in advance for
any time you spend responding!

James Hunter Ross
Senior Software Developer
O'Neil Software, Inc.
(e-mail address removed)

 

[JIMCO Software]

So what is an Application Restart, and why might it be happening
unexpectedly?

Any thoughts or words will be greatly appreciated. Thanks in advance
for any time you spend responding!

Hi James,

Each application is hosted in an application domain and that app domain is
hosted in an HttpRuntime object. The most common cause for an app domain
restart that is NOT associated with a process restart is file change
notifications.

Windows fires a File Change Notification event when files are modified.
ASP.NET listens for that event on the web.config in the root folder and in
the /bin folder. If a File Change Notification is fired on either, the app
domain unloads and the next request reloads it.

Common causes of this are anti-virus, indexing services, developers
modifying files or putting new files in the /bin folder, etc.

 

[James Hunter Ross]

Thanks so much Jim!

We'll start watching these directories/files very closely. We can't afford
to have unnecessary restarts.

James