Hi there @anwarul123,

The minimal memory recommended for both distros is quite similar based on the official documentation.

Also, the minimum memory requirements for VestaCP is 512M according to their official website, so my personal recommendation would be to go for the OS that you are more familiar with and would feel more comfortable maintaining. If you are used to CentOS and have been using it for a long period of time then you should go for CentOS and vice-versa.

Here is a great discussion on that topic:

https://www.digitalocean.com/community/questions/whats-is-better-and-why-linux-centos-or-ubuntu

Regards,
Bobby