Archiving and Deletion

Hi All

By default does any job is scheduled for archiving or deleting the messages in XI either in ABAP or Java Stack?

If not do we need to schedule archiving and deleting jobs.should we schedule these jobs separately on ABAP and Java stacks?

How to find the maximum size a server can accomdate or how to find the threshold level for the xi messages in the data base?

Regards

Bhasker