Trouble with big HDDs over 2TB at Raspbian

[Alexey]

Yes. If you want to add another HDD, the best way is to setup another node using different ports and generate a new unique identity, signed with a new authorization token, as described in the guide.

Any DDNS service will not help to forward ports, it can help only with dynamic public IP.
If your public IP from there: Open Port Check Tool - Test Port Forwarding on Your Router doesn’t match the WAN IP on your router - the port forwarding will not work and DDNS will not help.
In such case you have few options:

Noob here! My node shows offline all the time. I have tried opening the port using static and dynamic

You can try to call to your ISP and ask them for public IP, you can say that you need an access to your security IP cam from anywhere, this will allow you to do not explain Storj. The other way is to switch a ISP to the one who offer a public IP, it could be dynamic but must be a public (WAN IP match the public IP on yougetsignal). And the last option is to use VPN with port forwarding option such as portmap.io, ngrok, PIA, AirVPN, PureVPN, etc.