svn commit: r212964 - head/sys/kern

[Ken Smith]

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On 9/22/10 5:02 PM, Andriy Gapon wrote:
> on 22/09/2010 22:58 John Baldwin said the following:
> 
>> Agreed.  FWIW, I actually think that this is the only change needed as
>> crashinfo is enabled by default in 8.x and later.  We already include symbols
>> in kernels by default now, so just setting dumpdev will give you the same
>> info you generally can get from a textdump in the form of a simple
>> /var/crash/core.txt.N file.
>>
>> The other benefit of full crashdumps + crashinfo as compared to textdumps is
>> that a developer can request further information in a PR followup (fire up
>> kgdb and enter command 'X' and reply with the output).  With a textdump any
>> info not collected by the textdump is lost once the machine reboots after the
>> crash.
> 
> Agree++
> But what was the reason that dumpdev="AUTO" was reverted?
> I remember that POLA was quoted at the time.
> I am not sure what the astonishment actually was - perhaps 'AUTO' was not smart
> enough and destroyed somebody's data?
>


Not everybody would notice /var getting full of crash dumps.
Picture a server farm where for the most part the machines
are all just plain on auto-pilot.  If one or several develop
a problem that causes panic's /var can become full and possibly
cause the machine to stop doing something important (between
panic's...).  I wasn't around when the initial decision for
what to have it set to was made but this was the reason for
me starting to do it again when I realized I forgot to at
least once, and hence the reference to POLA.

Crash dumps are good for individual workstations.  Crash
dumps are good for servers *if* the admin knows they're
having a problem and is actively working on that server
to resolve the issue.  But they're no so good and can
cause nasty side-effects if they're happening on a machine
not being watched over closely.  That's the reason for
the change in setting when a -stable branch gets started.

- -- 
						Ken Smith
- - From there to here, from here to      |       kensmith at buffalo.edu
  there, funny things are everywhere.   |
                      - Theodore Geisel |
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