SharePoint Solution Deployment: How do I prevent SP from resetting IIS when upgrading or retracting a globally deployed solutions?

Question

So I figured out that by adding the ResetWebServer="FALSE" attribute to the solution manifest prevents SharePoint from recycling any app pools.

However, when upgrading a solution that originally did not specify ResetWebServer="FALSE" or when retracting a solution that does specify ResetWebServer="FALSE", the application pools are still being recycled. Is there a way to prevent any auto-recycling of app pools?

Answer 1

This does not seem possible given the document on MSDN (see below), note that I included Deploying a Solution over Upgrading a solution as underneath it is effectively doing a file replacement. I believe the restart/recycling is necessary as a result of how IIS functions. An option to explore if you wanted to manage when this occurs is to ensure that all deployments are done via timer jobs and execute when their impact will be minimized.

• Deploying a solution

Initially, manifest and feature manifests are parsed to find assembly and _layouts files, which are copied to the appropriate locations. All other files contained within a feature directory are copied to the feature directory. After solution files are copied to the target computers, a configuration reset is scheduled for all front-end Web servers; the reset then deploys the files and restarts Microsoft Internet Information Services (IIS).

• Retracting a solution

On each front-end Web server, the following occurs:

• Microsoft Internet Information Services (IIS) is disabled.
• Files are removed from the system.
• IIS is re-enabled and Windows SharePoint Services is reloaded when
  a user browses to a page.

Answer 2

You might also take a look at the "-local" switch. Didn't try it yet but it seemed that it allowed deployment server per server when you are in a load balanced situation.

Might be a good lead.