By default, there are at minimum 3 tablespaces which are very often used by AR System :
* ARSYSTEM
* TEMP
* UNDO
You should ensure you that there are on seperate disks and the TEMP tablespace is on the fastest disks.
You can also have multiple datafile per tablespace which are splitted onto different disks....
You have the possibility to add more tablespaces for AR System data and indexes. For example :
* ARSYS_DATA1
* ARSYS_IDX1
* ARSYS_DATA_ARCH1
* ARSYS_IDX_ARCH1
It's just an example... For some AR System application I had developped we have 16 tablespaces for AR System data and indexes...
Then you can move tables and indexes (using my Advanced Admin Tool which is available in the download section

) or use ardb.conf file to create new objects on the good tablespace or do both

: Move objects with the AAT and generate the ardb.conf file with perl script which is available on cummunity site.