Question

I was reading this.

I understand that application pool:

1. Can seperate the process so one work process fail won’t affect the
   other application in other application pool.
2. from the page above

different application pools to isolate applications helps prevent one
customer from accessing, changing, or using confidential information
from another customers site.

But,

1. How the worker process will fail? I only seen the situration that
   my asp.net application will throw an exception, but never seen a fail that will
   stop my whole worker process. Can someone give me a real life
   example?
2. And how it can prevent one customer from accessing, changing
   confidentail from other customers site? If the confidentail
   information are stored into database, isn’t that is not related? Or
   do they refers to something else?

Answer 1

1. Worker processs can fail due to memory leakage and if there is unhandled/uncatched exception thrown by web application running in the process. Worker process automatically restarts after failure but all users in the system will be affected.
2. Same thing for security if different all web applications share same worker process, attacking ione and causing it to crash will cause everything to crash.