11g AWR report shows wrong %idle and %iowait (Doc ID 842828.1)

Last updated on JULY 16, 2009

Applies to:

Oracle Server - Enterprise Edition - Version: 11.1.0.6 to 11.1.0.7
This problem can occur on any platform.

Symptoms

In 11g AWR report, there are two part of host CPU information available:

    Host CPU (CPUs:   32 Cores:   16 Sockets: ) 
    ~~~~~~~~         Load Average
                   Begin       End     %User   %System      %WIO     %Idle
               --------- --------- --------- --------- --------- ---------
                    1.15      1.37       1.9       0.3       0.2      97.8
    ====> %WIO is 0.2 and %Idle is 97.8
    Operating System Statistics - Detail    DB/Inst: NHI_HU/NHI_HU  Snaps: 538-540 
    
    Snap Time           Load    %busy    %user     %sys    %idle  %iowait
    --------------- -------- -------- -------- -------- -------- --------
    06-Jun 09:00:50      1.2      N/A      N/A      N/A      N/A      N/A
    06-Jun 10:00:19      1.1      2.3      2.0      0.3      0.3     97.7
    06-Jun 11:00:42      1.4      2.0      1.8      0.2      0.1     98.0
    ====> %idle is 0.1 to 0.3, and %iowait is 97.7 to 98.0

These 2 part of information are conflicated with each other and customer is confused which part is correct.

Cause

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