TCP packets lost?
Max Deineko <max@...
2008-01-07 07:55:43 GMT
I'm not really sure where to ask for help regarding my problem; I also
have posted to the apache group some time ago, but have not found a
solution. If you think this is the wrong group, I apologize. Also, any
hint as to where ask for help would be highly appreciated.
I'm facing following problem: Apache running inside an OpenVZ VPS,
serving multiple VirtualHosts. Now, it has regular availabiliy
problems, which appears to be neither load nor request pattern related.
What I don't quite understand is this: during the periods when the
server isn't available (and seems to do nothing) most of TCP sessions
look like the one below - apache keeps resending the handshake SYNACK
packets to the client although client's response is clearly here
(tcpdump done from inside the VPS).
Now I would think that even when the Apache proccess would hang, or be
waiting for some other component, the TCP stack part of the application
(or the kernel, for that matter) would still behave normally - is this
wrong? I.e. is such behaviour normal? Or do the incoming packets get
My first guess would have been that when the server is busy serving an
expensive request, the tcp rcv buffer would get full and packets would
get dropped. But wouldn't tcpdump not be able to see them then?
Any help would be highly appreciated,