Little research how rm -rf and tar kill server

Artem Kuchin artem at artem.ru
Mon Mar 30 16:17:12 UTC 2015


30.03.2015 19:09, Mark Felder пишет:
>
> On Mon, Mar 30, 2015, at 11:04, Artem Kuchin wrote:
>> 30.03.2015 18:57, Mark Felder пишет:
>>> On Mon, Mar 30, 2015, at 10:53, Artem Kuchin wrote:
>>>> This is normal state, not under rm -rf
>>>> Do you need it during  rm -rf  ?
>>>>
>>> No, but I wonder if changing the timer from LAPIC to HPET or possibly
>>> one of the other timers makes the system more responsive under that
>>> load. Would you mind testing that?
>>>
>>> You can switch the timer like this:
>>>
>>> sysctl kern.eventtimer.timer=HPET
>>>
>>> And then run some of your I/O tests
>>>
>> I see. I will test at night, when load goes down.
>> I cannot say sure that's a right  way to dig, but i will test anything :)
>>
>> Just to remind: untar overloads the system, but untar + sync every 120s
>> does not.
>> That seems very strange to me.  I think the problem might be somewhere
>> here.
>>
> I just heard from mav that there was a bottleneck in gmirror/graid with
> regards to BIO_DELETE requests
>
Well, i have plenty of CPU power left if you look at TOP screenshots. 
But i will try this patch too.
If i update sources of 10-STABLE and rebuild world will this patch be there?

But still, this does not explain why untar need fsync to pay nice.

Artem






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