Upgrade SQL 2008R2 to SQL 2016 on windows server 2012R2 I am checking for expertise opinion for IN PLACE UPGRADE from SQL 2008R2 to 2016. We have tested side by side which looks good in dev env's.

Considering production can i have some opinions on how feasible and safe is to use in place upgarde:


for standalone server upgrade
for cluster SQL FCI upgrade
Well, once you upgrade there is no going back. So that's a big danger in doing in place upgrades and why so many people don't do it. Some straight up won't do it for production. In place also has more downtime. 

Unless you're on a modern OS (2016 or 2019) I wouldn't do an in-place upgrade as it limits your supportability given WS 2012R2 ended mainstream support last year.