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. -- Francesco