[mirror-admin] Heads up if your running Fedora w/ a 2.6.27 kernel

[J.H.]

Jan Kasprzak wrote:
> J.H. wrote:
> : Just a quick heads up to any mirror that is running a 2.6.27 kernel.  If 
> : you are seeing segfaults in Apache like the following:
> : 
> : [Tue Jan 27 04:45:21 2009] [notice] child pid 5322 exit signal 
> : Segmentation fault (11)
> : [Tue Jan 27 04:45:23 2009] [notice] child pid 5496 exit signal 
> : Segmentation fault (11)
> : [Tue Jan 27 04:45:30 2009] [notice] child pid 5323 exit signal 
> : Segmentation fault (11)
> : [Tue Jan 27 04:45:32 2009] [notice] child pid 5327 exit signal 
> : Segmentation fault (11)
> : [Tue Jan 27 04:45:34 2009] [notice] child pid 5330 exit signal 
> : Segmentation fault (11)
> : [Tue Jan 27 04:45:36 2009] [notice] child pid 5332 exit signal 
> : Segmentation fault (11)
> : [Tue Jan 27 04:45:38 2009] [notice] child pid 5861 exit signal 
> : Segmentation fault (11)
> : 
> : and can't explain what's going on, there was a recent kernel change that 
> : effects epoll (which Apache switched to a while back) and causes you, by 
> : default, to only have 129 children running before Apache's children 
> : would segfault.
> : 
> : https://issues.apache.org/bugzilla/show_bug.cgi?id=46467
> : 
> : Just thought I'd share since I can't be the only one who has hit this in 
> : the last couple of weeks.
> 
> 	I ran into this a while ago, straced apache, and fixed it
> using
> 
> echo 'fs.epoll.max_user_instances = 1024' >> /etc/sysctl.conf
> sysctl -p

Same thing I did, though I was slightly more generous and kicked it up 
to 8192

> 
> 	IMHO the default kernel limit is too low.
> 

Considering it used to work, and after an upgrade it dropped to a max of 
130 children - probably not best choice for a server as a default.

- John 'Warthog9' Hawley

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