One of our databases is running on an unsupported version of AIX, and I have to move a datafile to free up some space in one of the volumes because the volume can't be resized. There are 3 datafiles in the volume, the biggest being the rollback datafile.

Before I boldly go ahead with moving this, thought I'd better double check...

shutdown the database
do an cp of the file to it's new destination
start the database up in nomount mode
alter database rename file "old" to "new"
shut the database down & restart
check dba_data_files & make sure file is in new location
delete the old datafile