How much IO is Imposed by System (Oracle)

Don’t forget to add extra IO imposed by users of the database. For example, to determine how much extra I/O will be imposed on the system when the new load is put into place. For example, if more users or reports will be added, determine how much I/O these reports (or a typical user) currently does, then extrapolate for the estimated growth. The query below will assist in getting some of this data.

SELECT a.sid,
a.statistic#,
SUBSTR(b.name,1,40) name,
a.value
FROM v$sesstat a,
v$statname b,
v$session se
WHERE se.audsid = (select userenv(’sessionid’) from dual)
AND a.statistic# = b.statistic#
AND se.sid = a.sid
AND b.name in (’physical read total IO requests’,'physical read total bytes’,'physical write total IO
requests’,'physical write total bytes’)
ORDER BY b.class, b.name