Our database is growing too big and performance is dropping.
Therefore, decision was made to vertical and horizontal database split.
Database schema is being broken into 8 schemes which will live within their own servers. To manage relationships between schemes we have decided to use web services.
My questions are:

How to modify our HBM files with the least amount of pain, ideally without any change to the business logic layer?

What can I do about Session/SessionFactory to manage lazy load via Web Service?

Any advice would be very appreciated.
Thanks in advance,
Gary

why did you choose such sollution?

more over which database are you using

and what is the root cause of performance

We are using MySQL 5. It is clustered and replicated (master + 2 slaves).
Performance problem caused by the size. Several mostly accessed tables have 100,000,000 - 500,000,000 rows.


We need to distribute data. Right now everything is in one location. We are trying to spread it among several data centers across the world to move data closer to the customers and reduce network traffic.
If you can offer better solution, I am all ears.