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Date:      Fri, 26 Jul 2019 15:39:55 +0300
From:      Christos Chatzaras <chris@cretaforce.gr>
To:        FreeBSD Questions <freebsd-questions@freebsd.org>
Subject:   Re: Help:: Listen queue overflow killing servers
Message-ID:  <8E871E29-53D5-4F88-A0B3-F1A3F966CF0B@cretaforce.gr>
In-Reply-To: <3a62375a-432c-3533-a7bc-e5573c26fa9c@ifdnrg.com>
References:  <3a62375a-432c-3533-a7bc-e5573c26fa9c@ifdnrg.com>

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Do you have "sendfile" enabled in Apache? If yes disable it and see if =
the issue is resolved.


> On 26 Jul 2019, at 14:58, Paul Macdonald via freebsd-questions =
<freebsd-questions@freebsd.org> wrote:
>=20
>=20
> Hi,
>=20
> Over the past few months i've seen several boxes (4 or 5) become =
unresponsive as a result of a Listen queue overflow state.
>=20
> Processes stack up, none are killable, all these are within jails and =
neither the jail can be stopped nor the server rebooted (without a power =
cycle).
>=20
> All are on ZFS and are std apache/php/mysql servers with nothing too =
exotic.
>=20
> All on 12.0-RELEASE, i've only started seeing these issues recently, =
but it feels like more and more.
>=20
> /var/log/messages shows tyically;
>=20
>     kernel: sonewconn: pcb 0xfffff813395e3d58: Listen queue overflow: =
193 already in queue awaiting acceptance (83 occurrences)
>=20
> netstat -Lan  shows
>=20
> tcp4 193/0/128                          x.x.x.x.443
> tcp4  193/0/128                          x.x.x.x.80
>=20
> connections cannot be killed with tcpdrop ( except ssh which can!)
>=20
> All processes seem to be in Disk State ( many many apache processes =
but others getting stuck too)
>=20
> www      60089    0.0 0.1  196588   78328  -  DJ   21:07         =
1:19.54 /usr/local/sbin/httpd -DNOHTTPACCEPT
> ..<snoip>
>=20
> www      93713    0.0 0.0  183576   33164  -  DJ   23:57         =
0:00.01 /usr/local/sbin/httpd -DNOHTTPACCEPT
>=20
> but no zombies..
>=20
> last pid: 24773;  load averages:  0.00,  0.00, 0.00                    =
   up 52+11:41:09  11:48:02
> 918 processes: 1 running, 917 sleeping
> CPU:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% idle
> Mem: 107M Active, 3729M Inact, 93G Wired, 27G Free
> ARC: 79G Total, 54G MFU, 23G MRU, 243M Anon, 710M Header, 1615M Other
>      73G Compressed, 191G Uncompressed, 2.60:1 Ratio
> Swap: 4096M Total, 4096M Free
>=20
>=20
> I'd appreciate any advice as at present it looks like my only option =
is to hard power cycle these
>=20
> many thanks
>=20
> Paul.
>=20
>=20
>=20
> --=20
> -------------------------
> Paul Macdonald
> IFDNRG Ltd
> Web and video hosting
> -------------------------
> t: 0131 5548070
> m: 07970339546
> e: paul@ifdnrg.com
> w: http://www.ifdnrg.com
> -------------------------
> IFDNRG
> 40 Maritime Street
> Edinburgh
> EH6 6SA
> ----------------------------------------------------
>=20
> Virtual Servers from =C2=A350.00pm
> High specification Dedicated Servers from =C2=A3150.00pm
>=20
> ----------------------------------------------------
>=20
> _______________________________________________
> freebsd-questions@freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-questions
> To unsubscribe, send any mail to =
"freebsd-questions-unsubscribe@freebsd.org"




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