Hi,

   Why the first execution of "iostat -c" always displays the same values?

[root@abc ~]# iostat -c
Linux 2.6.9-55.ELsmp (abc)         11/26/2010

avg-cpu:  %user   %nice    %sys %iowait   %idle
           5.62    0.00    3.08    3.30   88.00

[root@abc ~]# iostat -c
Linux 2.6.9-55.ELsmp (abc)         11/26/2010

avg-cpu:  %user   %nice    %sys %iowait   %idle
           5.62    0.00    3.08    3.30   88.00

[root@abc ~]# iostat -c
Linux 2.6.9-55.ELsmp (abc)         11/26/2010

avg-cpu:  %user   %nice    %sys %iowait   %idle
           5.62    0.00    3.08    3.30   88.00

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     When I use "iostat -c 1" the next values are modified:

[root@abc ~]# iostat -c 1
Linux 2.6.9-55.ELsmp (abc)         11/26/2010

avg-cpu:  %user   %nice    %sys %iowait   %idle
           5.62    0.00    3.08    3.30   88.00

avg-cpu:  %user   %nice    %sys %iowait   %idle
           2.00    0.00    4.00   23.25   70.75

avg-cpu:  %user   %nice    %sys %iowait   %idle
           0.75    0.00    1.74   24.38   73.13

avg-cpu:  %user   %nice    %sys %iowait   %idle
           0.25    0.00    0.50   24.56   74.69

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Reading the man pages os iostat, I could not understand these lines:

"The  first  report  generated  by the iostat command provides statistics concerning the time since the system was booted. Each subsequent report covers the time since the previous report."
"The first report contains statistics for the time since system startup (boot). Each subsequent report contains statistics collected during the interval since the previous report."


Why it can´t build a report with the current usage values at the first execution?

--
Att.
Bruno Galindro da Costa
bruno.galindro@gmail.com
http://www.thevenusproject.com/
http://www.arthurvinicius.com.br/