Oracle-L: RE: CPU WAIT I/O statistic

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Tue, 15 Oct 2002 13:33:28 -0800
Message-ID: <F001.004E9CEF.20021015133328@fatcity.com>

Pablo - You may be able to find some of the answers in Oracle and the O.S.

What does the O.S. I/O stats look like when you see this situation. Are the disks about to burn off the spindles? Or are they sitting idle?
What do the Oracle Wait statistics look like? What are the 3 big wait times?

Other than that, to get more specific definitions, I think you may want to find an O.S. list and ask the system administrators and system developers.

Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Tuesday, October 15, 2002 2:19 PM
To: Multiple recipients of list ORACLE-L

Dennis,

Thanks for your answers and your time.

I was interested in how the OS (Sun, AIX, HP, etc) classifies the CPU time used by the processes.

Taking a look at the WAIT I/O statistic taken with sar -u I started wondering what they really meant:

ie
%usr %sys %wio %idl
30 5 60 5

Does 60% (WIO column) mean that the processes actually used 60 percent of the CPU time (while they were waiting for I/O) ? If this is the correct answer, How did the consume this time?

May be this means that the I/O primitives (kaio, pwrite, write..) used the 60% of the CPU time...

it simple means that 60% of the processes that were executed have incurred in an I/O....

I Hope someone can shed some light on this. Thanks.

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Author: =?iso-8859-1?q?Pablo=20Rodriguez?= INET: p_rodri99_at_yahoo.es

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Author: DENNIS WILLIAMS
INET: DWILLIAMS_at_LIFETOUCH.COM

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