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On Wed, 16 May 2007, Brian Staszewski wrote:
Hey everyone. I implemented an LVS-NAT/ldirectord setup
for a web site and I'm having some strange problems. What
appears to be happening is that somehow the real servers
are not always able
^^^ ^^^^^^ ^^^^
sometimes they can, sometimes they can't?
to send data back to the client that
made the request. When I view apache's status page
(/server-status/) I'll see many connections in the "W"
(Sending Reply) state, and they'll stay there until they
either time out or I restart apache.
this is a strange one. This will require some tracking down.
do you have any iptables rules on the machines? If so, kill
them and have your firewalling done elsewhere for the
moment.
do you know anything about the requests that don't get reply
packets? do they go through a database, are they POST's, do
they retrieve gifs from other servers, do they have a packet
size divisable by 13 (j.k. but you're going to have to find
a pattern and neither of us know what to look for)
is there one request that you can make that will fail often
enough to test the problem, even if you don't know what's
characteristic about it?
does tcpdump tell you anything about the packets that aren't
getting through? is there a shower of icmps coming back for
these packets?
is the default gw for the affected server(s) being flipped
to the backup director? (force one director to stay as the
active director for the tests?)
I've tried with and without persistence, and it has made no difference.
persistence it to do with the forwarding, not the tcpip
layer.
Joe
--
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!
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