Hello, Maxim.

On Thu, 5 Apr 2012 18:56:11 +0400
Maxim Dounin <mdounin@mdounin.ru> wrote:

> Hello!
>
> On Thu, Apr 05, 2012 at 09:25:44AM +0900, shin fukuda wrote:
>
> > Hi.
> >
> > I have a problem with nginx-1.1.16 uses proxy_cache_lock on.
> > When high load or many request to nginx, Suddenly nginx seems hang,
> > no response at all.
> > In netstat "SYN_RECV","CLOSE_WAIT" too many. This problem needs
> > restarting nginx, and "CLOSE_WAIT" clear.
> >
> > There is no problem in front-end nginx servers, but backends one.
> >
> > Any clue?
>
> I would suggest you are hitting some system limits. Check nginx
> and system logs, as well as various system stats. Check the state
> of nginx worker processes, most importantly wait channel (wchan,
> "ps -alx" should show one at least on FreeBSD and Linux).

Set kernel parameter like

...
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_max_syn_backlog = 8192
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_fin_timeout = 15
net.ipv4.tcp_keepalive_time = 300

But, no good result so far.

Anyway, I check workers details, and find this,

15832 write(4, "2012/04/04 19:56:10 [info] 15832#0: sigtimedwait()
failed (4: Interrupted system"..., 87) = 87
15832 rt_sigtimedwait([ALRM IO RT_12 RT_13], 0x691220) = -1 EAGAIN
(Resource temporarily unavailable)
15832 rt_sigtimedwait([ALRM IO RT_12 RT_13], 0x691220) = -1 EAGAIN
(Resource temporarily unavailable)
....
....

Is this normal status ?


> Maxim Dounin
>
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> nginx@nginx.org
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--
shin fukuda <albert@nn.iij4u.or.jp>

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