I would be grateful if anybody helps me in getting an answer regarding VMware NSX-T Data Center licensing. If I have my DC and DR site, Do I need to purchase separate NSX-T licenses for both site ESXi hosts? I failed to get the answer from google.
My understanding is that you have to pay for all licensed host just like esxi. You do not have to pay for the licenses until you use them so in theory through some automation you can remove licenses from production and shift them over to DR but then Testing and such gets a little difficult. Not sure you want to deal with that during a DR event.
DR sites with no active workloads ( leveraging NSX features) do not require the purchase of NSX licenses. You can just prepare the Host in the DR site and keep it ready for any failover scenarios.
I would recommend checking https://kb.vmware.com/s/article/80866 . There are certain features that are specific to NSX-T, so always check the use case and scope the license accordingly.