there is no project in my railway yet to start so project-ID:N/A

yes

Both hobby and pro has storage via attachable volumes
Hobby allows for up to 5GB of storage per volume while Pro allows for up to 250GB of storage per volume

how you mention volume here like u said about docker volume or else
am talking about our raw database which running in RDS postgres

Yes it's pretty much Docker volumes, and yes you can use it for databases as well. You can right click on a project then click database and then you'll see an option for Postgres right there

We already purchase the Hobby plan try to migrate our Postgres DB size with 600MB but hobby plan is only for 512 MB so it got failed so what else i want to do form my end and what are the other ways to mirgate and deploy my db and application

Hobby has 5GB of storage, not 512mb, if your volume is 512mb on hobby plan then you can increase the size in the volume's settings

all clear to solve?

assuming all clear, feel free to open anothet thread if you have more questions

!s