svnadmin dump or
svnadmin export will only has a snapshot of a certain version.
How to keep all change logs when immigrating to another server?
Will it be OK to just copy the
/repositories over there?
svnadmin dump will create a 'backup' of your entire repository, you can then restore it into a new repository using svnadmin load. This is a full backup/restore and will maintain your history as recommended by the book.
If you're moving your repo to the same operating system (eg windows to windows, or linux to linux) then you can safely copy the repo directory. Some people say you should update the repo's UUID (svnadmin setuuid), but that'd not strictly necessary.
If you're migrating between OSs, then dump/load is your only option.