Good, but i already do it to without much problems (Except procedures, you need to re-create all of them or just simple change server side logic)
The problem still in server design anyway not only at field as varbinary or something else bro.
Indeed, that's why we created new software really from scratch.
Also the main reason why we decided to make a new server was to learn new techniques and how to apply them. That helps a lot when you want to start your own project or even improve your own.
The final result is:
LoginServer (acts like old ConnectServer & JoinServer).
GameServer (old GameServer & DataServer).
ServerLink (old ExDB).
We don't use a DataServer. All character related Query are on GameServer, and we use CallBack to get results so gameserver won't freeze or be delayed because of that (screenshots at the end).
We use something similar to ExDB, but we called ServerLink because it connects every gameserver of same group (Like code from 0 to 19). This softwares manages Chat between gameservers (post, whisper, ...), Guild, Castle Siege, Crywolf & Arka War (everything that should be applied on every gameserver). This software handles all queries related to those events i listed.
This one is a Callback after verifying if a selected character to Login exists. It returns character GUID that is what we use to connect data between tables.
http://puu.sh/Bq7zS/2db5b9e93b.png
We use the information obtained above to create a Query Holder that will load all character data and will return to a callback function.
http://puu.sh/Bq7Dj/2db42e80d8.png
And this is the callback function
http://puu.sh/Bq7FF/19b279c8ba.png
And this is how a function that loads information looks like
http://puu.sh/Bq7J4/5e464b373a.png
IMPORTANT:
The reason why i explain all this and show what we have done is NOT to say that old system is bad and our system is good. I just want to show that, if you want, you can create your own server.
Of course you may encounter problems during the process, we struggle a lot until we finally got something stable.
Also is a fun process too, you are going to like it.