On Tue, Jan 22, 2013 at 10:17:50AM -0800, Rick Jones wrote:What is important is the backlog, and I guess you didn't increase it
properly. The somaxconn default is quite low (128)
Leandro -
If that is being overflowed, I believe you should be seeing something like:
14 SYNs to LISTEN sockets dropped
in the output of netstat -s on the system on which the server
application is running.
What is that value reporting exactly?
Because we are using syncookies, and AFAIK with that enabled, all
SYNs are being replied, and what the listen backlog is really
limitting is the "completely established sockets waiting to be
accepted", according to listen(2). What I don't really know to be
honest, is what a "completely established socket" is, does it mean
that the SYN,ACK was sent, or the ACK was received back?
Also, from the client side, when is the connect(2) call done? When the
SYN,ACK is received?
What I'm seeing are clients taking either useconds to connect, or 3
seconds, which suggest SYNs are getting lost, but the network doesn't
seem to be the problem. I'm still investigating this, so unfortunately
I'm not really sure.