What kind of device is the file on? SAN, NAS, or local attached Disk?
David VanZandt
Please post the relevant section of your alert log, in which the create tablespace DDL is issued and the resulting messages. What happens after 20 minutes - is the command being aborted by the user? Can you successfully create a smaller datafile, say 5 Gb? And of course, are you absolutely sure the target file system(s) have sufficient free space?