We are about to deploy a bunch of sites to some new servers. I have the following questions about application pools:

1) It seems advisable to have an application pool per website. Are there any caveats to this approach? Can one application pool, for example, hog all the CPU, Memory, Etc...?

2) When should you allow multiple worker processes in an application pool. When should you not?

3) Can private memory limit be used to prevent one application pool from interfering with another? Will setting it too low cause valid requests to recycle the application pool without getting a valid response?

4) What is the difference between private and virtual memory limits?

5) Are there compelling reasons NOT to run one application pool per site?

Thanks!