RE: mod_jk causing stuck Apache processes

[Jesse Defer <Je...@asu.edu>]

> >> any update on the behavior of the patched nodes? Did it behave better,
> ie.
> >> did the problem reoccur on other nodes but not on the patched ones,
> >> or were all nodes mostly without problems during the last 2 days? Any
> >> strange things on the patched ones? I'd like to add the patch for
> >> 1.2.41 but your feedback would be very valuable.
> >>
> >> Thanks!
> >>
> >> Rainer
> >
> > It's been quiet, no stuck processes anywhere in the farm.  The patched
> > jk is working fine, no issues found so far.  I'll continue to monitor
> and let you know.
> 
> Just to make sure: "no stuck processes anywhere in the farm" means we
> can't be sure, that the patch helps, because the unpatched nodes didn't
> have a problem either during that time. So we have to wait until the
> problem happens a few more times so we can see whether the patch helps, or
> the patched nodes have run long enough so that at least we don't expect a
> negative impact from the patch.

Rainer,

The patch has not completely fixed the issue, I had a host today exhibit 
the behavior.  It does seem to have better behavior: stuck process don't hang 
around as long though there are still some >300 second ones.  It also seemed 
to recover by itself, though it took about 40 minutes.  It also had more
idle processes on average, though it did hit 90% in W for a few minutes.

I have also converted 4 (different) hosts to the event mpm and was tweaking 
the mpm settings all last week.  I think they are in a good state now and
so far I haven't seen the issue on them.

I now have 8 on stock mod_jk/prefork, 4 on your patched mod_jk/prefork, and 4 
on stock mod_jk/event.

We are upgrading to httpd 2.4.12 on Friday and I am also gone on vacation 
all next week.  We haven't decided yet if we are switching to event at the 
same time, but it seems likely.  I am willing to continue testing your 
patch but I won't be able to resume until the week of the 16th and it may 
not be under prefork.

Respectfully,

Jesse

Re: mod_jk causing stuck Apache processes

[Rainer Jung <ra...@kippdata.de>]

Am 03.03.2015 um 23:11 schrieb Jesse Defer:
>>>> any update on the behavior of the patched nodes? Did it behave better,
>> ie.
>>>> did the problem reoccur on other nodes but not on the patched ones,
>>>> or were all nodes mostly without problems during the last 2 days? Any
>>>> strange things on the patched ones? I'd like to add the patch for
>>>> 1.2.41 but your feedback would be very valuable.
>>>>
>>>> Thanks!
>>>>
>>>> Rainer
>>>
>>> It's been quiet, no stuck processes anywhere in the farm.  The patched
>>> jk is working fine, no issues found so far.  I'll continue to monitor
>> and let you know.
>>
>> Just to make sure: "no stuck processes anywhere in the farm" means we
>> can't be sure, that the patch helps, because the unpatched nodes didn't
>> have a problem either during that time. So we have to wait until the
>> problem happens a few more times so we can see whether the patch helps, or
>> the patched nodes have run long enough so that at least we don't expect a
>> negative impact from the patch.
>
> Rainer,
>
> The patch has not completely fixed the issue, I had a host today exhibit
> the behavior.  It does seem to have better behavior: stuck process don't hang
> around as long though there are still some >300 second ones.  It also seemed
> to recover by itself, though it took about 40 minutes.  It also had more
> idle processes on average, though it did hit 90% in W for a few minutes.
>
> I have also converted 4 (different) hosts to the event mpm and was tweaking
> the mpm settings all last week.  I think they are in a good state now and
> so far I haven't seen the issue on them.
>
> I now have 8 on stock mod_jk/prefork, 4 on your patched mod_jk/prefork, and 4
> on stock mod_jk/event.
>
> We are upgrading to httpd 2.4.12 on Friday and I am also gone on vacation
> all next week.  We haven't decided yet if we are switching to event at the
> same time, but it seems likely.  I am willing to continue testing your
> patch but I won't be able to resume until the week of the 16th and it may
> not be under prefork.

Thanks for your efforts.

I have committed the changes to mod_jk in 1665454. They will be part of 
version 1.2.41.

Regards,

Rainer

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