Originally posted by: SystemAdmin

Hi,

I would like to know if there is an option to disable
saving of system dump in AIX 5.3 when a kernel panic occurs.

And is there any other way to invoke a user induced panic other than
using sysdumpstart.

Thanks,
Kanna
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Originally posted by: MarkTaylor

>> I would like to know if there is an option to disable
>> saving of system dump in AIX 5.3 when a kernel panic occurs.

Why would you want to do this ?

Set your dump devices to /dev/sysdumpnull

>>And is there any other way to invoke a user induced panic other than
>>using sysdumpstart.

Again, why would want to do this ?

No, sysdumpstart is the correct way .. You used to be able to "echo crap > /dev/kmem" .. but I think that has been stopped in recent version .. give it a go .. If it works then it should give you a DSI 300

HTH
Mark Taylor
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Originally posted by: SystemAdmin

Thanks Mark..

But using the sysdumpstart on the dump device sysdumpnull is giving the
following error..

#sysdumpdev -p /dev/sysdumpnull
#sysdumpstart -p
sysdumpstart:
Cannot start dump to a NULL device, /dev/sysdumpnull.

I need this because I want to simulate a kernel panic without dumping, and I need
the system to come up quickly(without generating and copying the dump from the dump
device to the copy directory).

Thanks,
Kanna
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Originally posted by: SystemAdmin

Hi Kanna,

The whole idea of sysdumpstart is to collect a system dump. If you disable the collection it is as good as pulling the plug and switching on the server again. So you are attempting something which sysdumpstart cannot do.

If you have a HMC try restarting the LPAR with the DUMP option. Other than that I doubt anything else would work.

Regards,
R.
#AIX-Forum

Originally posted by: Casey_B

Not sure what you are testing, are you perhaps testing HA fallover?
If so, "halt -q" is more common to test...it is different from a system panic,
but it doesn't run any of the stop scripts, or orderly shutdown activities. (Not even sync)

You can disable the copy on boot flag to gain some time.
Did you try having an existent, but too small dump device?
The dump will fail, but maybe allow you to perform your testing.

Hope this helps,
Casey
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Originally posted by: Kosala

"echo crap > /dev/kmem", this step might need to change the permission on the file to 755 before trying this.
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