Move SAPDB

I want to move a SAPDB 7.4 from a Windows 2000 server to a different server running windows 2003... The DB is currently 21Gb and have several volumes!

Can you please describe the best way to move this???

Should i create the backup online or i should do it on admin mode?

This SAPDB is currently working a Content Server.

Thansk & Regards

Juan Reyes!