Oracle OEM show a chart of disk performance, as shown in the chart below. when the OEM target database is 10gr2, the number of average disk response time (ms) is 0.01 ms, which unreasonable low. when the target database is 11gr2, the number is about 10ms, which I think is reasonable. it's time to find out where the discrepency comes from. The backend query is this one: set linesize 200 col name format a9 col path format a19 --col MB_per_sec format select t3.name,t2.name,t2.path,t2.reads,t2.read_time,round(t2.read_time/t2.reads*1000,3) rd_rspd_ms,t2.writes,round(t2.write_time/t2.writes*1000,3) wr_rspd_ms, round((t2.read_time+t2.write_time)/(t2.reads+t2.writes)*1000,3) dsk_rspd_ms,round((t2.bytes_read+t2.bytes_written)/1024/1024/(t2.read_time+t2.write_time)) MB_per_sec from V$asm_disk t2, v$asm_diskgroup t3 where t3.group_number=t2.group_number order by 1,2 / NAME NAME PATH ...
stty erase \^h
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