I have a tablespace for example (with several DMS containers - raw devices) that is, let's say 50GB of size (total).
The tablespace is 25% used.
My first question is:
1. If I drop the tablespace and re-create it with total size of 25GB will the percentage of used space increase to 50%?
2. What is the best way to accomplish the above? (i.e tablespace backup or export/import)
Take complete db backup before you try any tricks.
Then perhaps you can try a redirected restore on a test box. During this you can allocate new containers of lesser size to this tablespace. Try this on a test box before you do anything on production though.