I want to receive messages from various sources on my central server. What should be the hardware configurations for it?
It depends on the average and expected number of messages that each of the devices will generate.
In general, you can write the syslog data to a SQL database. HOWEVER, the SQL server performance is a key issue with such an approach. Even if the devices have moderate load, you need to highly optimize the SQL server backend and you probably also need multiple receivers. To learn more about this check out the article entitled performance optimizing syslog server.