Script will create a report of reads,writes on your data files

col PHYRDS   format 99,999,999
col PHYWRTS  format 99,999,999
ttitle "Disk Balancing Report"
col READTIM  format 99,999,999
col WRITETIM format 99,999,999
col name format a30
select name, phyrds, phywrts, readtim, writetim
from   v$filestat a, v$dbfile b
where a.file# = b.file#
order by readtim desc;