Varnish child killed

[Jean-Francois Laurens]

HI Thiago !

Thank you a lot for your very interesting comment !

In fact I get the same limitation with a 8GB memory server.

Please correct me if I¹m wrong :
My system has only 8GB of memory. Thus I can assume that the kernel should
have stared to write dirty mmap'ed pages longer in advance than your server
does.

But the very high loads I¹ve seen are only occuring once the cache became
close to 20GB+.
Why is that ? I still don¹t understand this 20GB+ limitation.

I addition of the vmstat and ps that I collect regularly, I will add an
iostat to watch the disk activity.


Jef


Le 27/04/11 00:26, « Thiago Figueiro » a écrit :

> From: Jean-Francois Laurens
> 
>> > Hi there,
> 
>> > Apr 20 21:48:43 server-01-39 varnishd[21087]: Child (5372) not responding
>> > to CLI, killing it.
> 
> Hi!  I'm a bit late to the discussion (happy Easter everyone!) but we came
> across this issue on Linux earlier this year.
> 
> You didn't send charts for your disk IO but I'm betting it looks busy.  If
> this is so, it may be the kernel pre-empting writing of dirty mmap pages to
> disk.
> 
> I investigated the issue at the time and found that on the RHEL 5 vanilla
> kernel the Varnish child was being blocked by kernel IO. This caused the
> parent pings to time-out:
> 
> http://microrants.blogspot.com/2010/07/varnish-and-linux-io-bottleneck.html
> 
> 
> TL;DR: 
> echo 0 > /proc/sys/vm/flush_mmap_pages
> 
> 
>   
> Good luck,
> Thiago.
> 
> 
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