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

W dniu 2014-02-12 14:11, Amos Jeffries pisze:
> On 13/02/2014 1:59 a.m., Pawel Mojski wrote:
>> W dniu 2014-02-12 13:54, Kinkie pisze:
>>> 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.
>> So. Just to clarify.
>> From tcp point of view: squid is not able to establish connection with
>> origin server. Thats all.
>> After sending SYN packet no ACK is reponded. SYSERR=100 cannot means
>> that squid was able to connect but no response was returned in some
>> period of time. Am I right?
> Whether or not that is right the ERR_CONNECT_FAIL is only produced on
> SYN errors.
>
> If Squid were able to connect but no HTTP response it would be a
> ERR_READ_ERROR, ERR_READ_TIMEOUT or ERR_ZERO_SIZE_OBJECT.
>
> Amos
Thanks Amos;

Now I know what is wrong and have to figure out why.
So, if it's not squid related problem I'll not boder you any more with
this case.

Best Regards;
Pawel Mojski
Received on Wed Feb 12 2014 - 13:27:01 MST