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@xxxxxxxxxx> wrote: >>> W dniu 2014-02-12 13:30, Kinkie pisze: >>>> On Wed, Feb 12, 2014 at 12:40 PM, Pawel Mojski <pawcio@xxxxxxxxxx> 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
