RE: 100% CPU

Kirti - Excellent point, as always.

The other aspect is the balance between interactive and batch work. We have a system that runs at 100% every month-end. Yes, we should add more hardware, aren't because we plan to migrate to another box and adding another CPU would be expensive because of Oracle licensing. But the key is that process priority is set correctly so that interactive processes receive prompt attention despite a report that runs for hours. Dennis Williams
DBA, 80%OCP, 100% DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Tuesday, May 20, 2003 7:02 AM
To: Multiple recipients of list ORACLE-L

Agree.
So, instead of buying more hardware (or upgrading it) an investigation into the cause of the 'over use' of the hardware is in place :)

• Kirti

-----Original Message-----
Sent: Monday, May 19, 2003 11:47 PM
To: Multiple recipients of list ORACLE-L

In defence, it's not the spinning disk but the head flying all over the disk which is likely to fail from over use.

Having said that I'm a big proponent of using available hardware. Hardware is a commodity to be used, not protected and viewed from a distance. If I wear a harddisk out sooner because I've done lots of work with it then that's fine.

Performing an item of work is a bit like filling a bathtub with water in this sense. I can turn the tap on fast and fill it quickly, or just turn it on a little bit and fill it slowly. Which approach uses more water? Neither. Which gets the job done quicker? The first option. What's the benefit of the second option? Nothing really - unless you like the sound of running water.

Note: There is a big difference between 100% utilisation and inefficient use... I hate inefficient use. :-)  

                      "Deshpande, Kirti"

                      <kirti.deshpande_at_v        To:       Multiple
recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>                  
                      erizon.com>               cc:

                      Sent by:                  Subject:  RE: 100% CPU

                      root_at_fatcity.com

 

 

                      20/05/2003 13:31

                      Please respond to

                      ORACLE-L

 

 

Sorry, but I thought the Hard Disks inside the disk arrays spin all the time. So, are those wearing out faster?

• Kirti

-----Original Message-----
Sent: Monday, May 19, 2003 9:27 PM
To: Multiple recipients of list ORACLE-L

>From: Mladen Gogala <mgogala_at_adelphia.net>
>Subject: Re: latch free - library cache
>
>So, what is spending the CPU? Why is a CPU running pedal to the medal a
>problem?
>I thought that CPU hardware was bought in order to run and not to sit
idle?
>The same goes for the memory. There are some people, mostly known as sys
>admins
>that will try telling you that "we need to keep CPU / memory N
>0.000000ree". Well,
>hardware is bought to be utilised. Nobody will stop a CPU for speeding
>(unlike myself and my passion for speeds above 80mph). CPU running at 100
>0s not a problem. An application not performing adequately is a problem.

Someone telling you that the cpu should be at zero percent is just being silly, however running at 100% is not an optimum condition. As one of the evil Sys Admins that you mentioned, I personally prefer my servers to not go
over 30% utilization on average, and prefer spikes to stay under 70%. If your hardware is running full bore all the time, two things will happen 1) Your hardware will wear out faster, especially hard drives, and 2) Your users will notice a slowed response time and complain. I'd say any server that runs over 50% usage on a regular basis is probably a good candidate for
either an upgrade or some load balancing. These figures can vary some with

your budget and business needs but as a generic rule I think many peopel will agree with me in principle. Besides, if you're running at 100% during

normal usage, what happens when a spike comes along like a shift change? Your server is going to lag, and users will be affected.

Chris Berry
compjma_at_hotmail.com
Systems Administrator
JM Associates

"What does it mean when they tell you your budget and it's a negative number?"

_

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