sanjay nadkarni (Laptop) wrote:
> Mike Gerdts wrote:
>   
>> On Wed, Jul 2, 2008 at 10:08 AM, David Magda <[EMAIL PROTECTED]> wrote:
>>   
>>     
>>> Quite often swap and dump are the same device, at least in the
>>> installs that I've worked with, and I think the default for Solaris
>>> is that if dump is not explicitly specified it defaults to swap, yes?
>>> Is there any reason why they should be separate?
>>>     
>>>       
>> Aside from what Kyle just said...
>>
>> If they are separate you can avoid doing savecore if you are never
>> going to read it.  For most people, my guess is that savecore just
>> means that they cause a bunch of thrashing during boot (swap/dump is
>> typically on same spindles as /var/crashh), waste some space in
>> /var/crash, and never look at the crash dump.  If you come across a
>> time where you actually do want to look at it, you can manually run
>> savecore at some time in the future.
>>
>> Also, last time I looked (and I've not seen anything to suggest it is
>> fixed) proper dependencies do not exist to prevent paging activity
>> after boot from trashing the crash dump in a shared swap+dump device -
>> even when savecore is enabled.  It is only by luck that you get
>> anything out of it.  Arguably this should be fixed by proper SMF
>> dependencies.
>>   
>>     
> Really ? Back when I looked at it, dumps were written to the back end of 
> the swap device.  This would prevent paging from writing on top of a 
> valid dump.  Furthermore  when the system is  coming up, savecore was 
> run very early to grab core so that paging would not trash the core. 
>
>   
I'm guessing Mike is suggesting that making the swap device available 
for paging should be dependent on savecore having already completed it's 
job.

    -Kyle

> -Sanjay
>
>   
>> --
>> Mike Gerdts
>> http://mgerdts.blogspot.com/
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>>   
>>     
>
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