Hi!
Setup CHR in my VPS. HDD space 50GB. After first boot - router os resize disk, remains 15GB.. Where is the rest of the disk space?

50gb? What for to start with? I run CHR on a 128MB disc. That is MEGAbytes, not GIGAbytes. What are you storing on 50gb?

Hi!
Setup CHR in my VPS. HDD space 50GB. After first boot - router os resize disk, remains 15GB.. Where is the rest of the disk space?

Had a vague memory that they limited the size of CHR disk in a release so I made a search in the change logs and I found the following:

What's new in v6.40 (2017-Jul-21 08:45):

*) chr - maximal system disk size now limited to 16GB;

Support answered - there are no disk limitations. Who is right?

Maybe both are correct?
System disk size can only be up to 16GB however that does not stop you adding additional disk at a size of your choice?

however, RouterOS does not leave me the opportunity to manage disk space. How do I add a disk?

If you add it through ESXi as you normally would then it should present in RouterOS as "Disk1" or similar.