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TOC button vs power switch

 
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martin_215
Frequent Advisor

TOC button vs power switch

what is the difference between TOC button and a power switch button
Is TOC something like processor reset without clearing cache and memory?
3 REPLIES 3
Patrick Wallek
Honored Contributor
Solution

Re: TOC button vs power switch

TOC = Transfer of Control = Forced System CRASH - This means that, when that button is pressed, your machine will CRASH, and a crashdump will be generated in /var/adm/crash (if you have that enabled, which you should). Pressing that button is a last resort if/when you are having serious system problems. The crash dump that gets generated can be analyzed by HP to troubleshoot the problems.

Once the machine comes back up, everything is restarted, pretty much like you rebooted the system. The only problem is, if you happen to be running a database or any applications or processes were running, you could have data integrity issues since nothing was stopped cleanly when you forced the crash.

The power button, depending on the system, can run some shutdown scripts so things come down relatively cleanly and then powers off the machine. Not all machines have that function. If you just press the power button, it is essentially like crashing the machine. You just pulled the rug out from under the systems feet. There is no telling what state things will be in when you power the system back on.

The power button should never be used unless you have done a 'shutdown -h' and you get the message 'OK to power off' (or whatever it is.
Alexander M. Ermes
Honored Contributor

Re: TOC button vs power switch

Hi there.
Be careful. The crashdump could be the size of your memory. We had that on a V2500 with 12 GB, so guess, waht happened. We had to cut it off.
Just my 2 ct.
Rgds
Alexander M. Ermes
.. and all these memories are going to vanish like tears in the rain! final words from Rutger Hauer in "Blade Runner"
Trond Haugen
Honored Contributor

Re: TOC button vs power switch

Just to add to the previos answers;
Power should only be turned off when the systems is down. If you can't shutdown the system you should do a TOC even if you don't plan to have HP analyze the dump. (You never know if you change youe mind later..)

If you dump is set up correctly the dump should be no where near the size of RAM.
When dumping (to dumpdevice/swap) only selected parts of memery is dumped. When savinig the dump after reboot it is compressed (gzip).

Regards,
Trond
Regards,
Trond Haugen
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