Question: How can I tell if my OS is
busy? I want to know if my hardware is overloaded when
Oracle is processing.
Answer: You can display OS (CPU and RAM) with
many scripts, and see the
Oracle script
collection for a complete OS script collection.
Also see my
notes on
monitoring UNIX/Linux CPU.
If you suspect a OS utilization problem, see
these important notes on 100%
CPU and Oracle. Also see
Oracle and OS utilization metrics.
This script
will display OS busy statistics
select
'OS
Busy Time' series, to_char(snaptime, 'yyyy-mm-dd hh24
hh24:mi') snap_time,
round(busydelta / (busydelta
+ idledelta) * 100, 2) "CPU Use (%)"
from
(select
s.begin_interval_time snaptime,
os1.value - lag(os1.value) over (order by s.snap_id)
busydelta,
os2.value - lag(os2.value) over (order by s.snap_id)
idledelta
from
dba_hist_snapshot s,
dba_hist_osstat os1,
dba_hist_osstat os2
where
s.snap_id = os1.snap_id
and
s.snap_id = os2.snap_id
and
s.instance_number = os1.instance_number
and
s.instance_number =
os2.instance_number
and
s.dbid = os1.dbid and s.dbid = os2.dbid
and
s.instance_number = (select instance_number from v$instance)
and
s.dbid = (select dbid from v$database)
and
os1.stat_name = 'BUSY_TIME'
and
os2.stat_name = 'IDLE_TIME')
