Re: [squid-users] Debuging ERR_CONNECT_FAIL with SYSERR=110

On Wed, Feb 12, 2014 at 1:49 PM, Pawel Mojski <pawcio_at_pawcio.net> wrote:
> W dniu 2014-02-12 13:30, Kinkie pisze:
>> On Wed, Feb 12, 2014 at 12:40 PM, Pawel Mojski <pawcio_at_pawcio.net> wrote:
>>> Hi All;
>>>
>>> I have pretty loaded squid server working in interception mode.
>>> In about 0.5% of total http request I have an ERR_CONNECT_FAIL with
>>> additional error SYSERR=110.
>>> How can I debug a reason of those errors?
>>>
>>> The thing which consider me a lot is the URL and remote server of those
>>> requests.
>>> For example, I found three same requests for the same URL hosted on the
>>> same IP request.
>>> The first one finished with response 200, the second with 503 and
>>> ERR_CONNECT_FAIL(SYSERR=110) and the third with 200 again.
>>>
>>> Also, my customers complains that sometimes "they have problems surfing
>>> the web".
>>>
>>> What can I do to debug the problem?
>> Hi Pawel,
>> SYSERR 110 on Linux is connection timeout (ETIMEOUT).
>> It would seem to indicate network issues somewhere, or a severely
>> overloaded server (which has used all its syn backlog)
>>
>>
> Hi Kinkie;
>
> I thought the same, but, I have huge net.core.netdev_max_backlog and
> net.ipv4.tcp_max_syn_backlog and there are no network related problems
> at all.

The error is reported by squid, but the issue is on the origin server, if any.

> At the same time when squid reports a problem I can connect manually
> from squid box to the same ip address (through telnet, wget, etc) and
> nothing wrong occurs.
> I even can belive somewhere somekind of timeout happened but how can I
> find out what type of timeout it is? syn/ack, wait, whatever?

It should be waiting for syn/ack.

-- 
    Francesco