[otrs] OTRS 2.4.7 - Mysql database max size support

Hi,   I am using OTRS 2.4.7 on Linux with Mysql Database.   Data size is 13 GB.   Please let me know what is the max size it can support without affecting the performance.   Of late I am experiencing that the respone is slow, it is beacuse of the BIG size of database?   regards, Amit