Thanks David for your response. Could you please share if any big enterprises rollout out OTRS on Mysql and running successfully till date?
I know of several I've done (600-700 agents, 2500-3000 significant issues/day, fairly large CMDB). Key issues are hardware performance (the OTRS front end can be resource intensive if heavily used; good idea to NOT run it on the DB servers...) and planning for fault management in the DBMS itself; eg clustering, replication. The ITSM add-ons are quite good, actually; change management will take some thought to implement, but that's not MySQL related (CM is hard on any tool). Pretty much the standard issues for any incident management system.
I am asking because we don't have choice other than going to Mysql due to future standardization of the technology rod-map.
Gotta do what you gotta do. I personally have suspended new MySQL deployments for OTRS until Oracle shows their cards, but YMMV.