Hi, you can increase the size of dbspace only by adding additional chunks.
You can do it with "onspaces -a dbspacename -p path_to_device_or_file -s size -o offset" command.
If you want to move database to another dbspace the most simple way is:
Export the database. dbexport dbname
Drop the database.
Import the database into the dbspace you want. dbimport dbname -d
dbspacename -l buffered ( Use buffered only if you want buffered