There are 500 Computers on my network We have planned to upgrade all Computers to windows 10. Currently we are using windows 7. Our Microsoft Partner suggest to upgrade our active directory OS to server 2019. We have 3 AD domain controllers which is running on server 2012 r2. But i don't have a requirement to change AD OS. Although server 2019 has more features,still we are not using all features in server 2012. Can you suggest what will be best solution.
I believe your MS partner is referring to the domain level.
If you already running on domain level 2012 it is not a requirement to raise the domain level to use windows 10.
There are a lot of considerations you need to take before raising the domain level, So I would recommend doing some research on this before raising it.
Upgrading the servers is not necessary. You can upgrade the clients and AD will not be affected. Upgrading the servers would be nice but it is not required to meet your stated goals. It sounds like your MS partner just wants to make a sale.
No, upgrade of AD is not necessary. Just make sure you take it into account before Windows 2012 is EoL.