Q:

Move-SPSite vs Copy-SPSite

In my environment I need to perform a Move-SPSite and a Copy-SPSite.
Why do Move-SPSite need a IISreset and Copy-SPSite do not?
Can I just use a Copy-SPSite (and delete one db) to avoid IISReset?

A:

That,s correct, when you run the Move-SpSite command, it require the IIS reset. Usually we do IISreset on all server in farm But what i tested so far.
Once we run the Move-Spsite command after sucessful, Run the IIS reset only on Central Admin box and it will update everything.You dont need to reset IIS On WFE so no outage for end user.
Copy-SPSite. make a copy of site collection in same web application and keep the original site collection.
Move-SPSite. Move the site collection(not making the copy) entire from to destination DB.
Check this excellent blog from Todd O. Klindt: Using Copy-SPSite to rename Site Collections in SharePoint 2013

