Unloading a live database

Hi, I need to unload a "database" while the instance is running and accepting updates on the database. I see that the "onunload" utility of Informix takes a lock on the database and does not allow users to modify the Database during the unload process. The unloaded database is to be loaded into another instance which need not have the same DBspace configurations as the first instance. This seems to rule out the use of archiving utilities like "ontape" which require identical DBspace configurations for a restore. I'd appreciate your input into solving this problem. Thanks. Alanoly J. Andrews