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On Fri, 5 Oct 2001, Kris Odland wrote:
> Here's whats going on. We are using LVS for load balancing imap servers,
> we have the tunneling option set up so the individual servers reply to
> the client.
I don't have an answer, but I do have some more questions..
I assume all the imap realservers are writing to one common filesystem?
> We are seeing a problem if you have your email client set up to copy
> sent messages to a "Sent" folder on the imap server. The client opens
> a seperate connection to the imap server for the sent folder.
Is this to the same VIP:port as the first connection?
If it's different, you could be connecting to a different realserver
than for the first imap connection. Is this a problem?
The
> problem is if you are typing a message and you have it open for a while
> (20 or 30 minutes) the imap connection for the sent folder is timed out.
> It tries sending it through the old connection (port) and gets "Port
> Unreachable" error from the imap server (not the LVS server) when it tries
> copying the message to sent mail. It will re-open the connection after a
> bit, but not when it is trying to to the sent mail thing.
The tcp connection through the director will be dropped in about 15mins
(depending on your kernel).
http://www.linuxvirtualserver.org/Joseph.Mack/HOWTO/LVS-HOWTO-11.html#ss11.30
> It seems that after 30 minutes the imap server sends a "BYE" message
> because it has been idle too long, and it does an autologout for the
> corresponding folder. This should be followed by a FIN, and then ACK from
> the client. In this case the ACK is not making it to the server, but
> being rejected with "Port Unreachable" messages, so the server keeps on
> trying to close the connection.
I would assume this is because the director has already dropped the link
(look at the output of ipvsadm if you can do it with a machine and only
one connection and you can sit around and wait - you could reduce the
tcp timeout as listed above to speed things up a bit).
Joe
--
Joseph Mack, mack@xxxxxxxxxxxx
Linux Virtual Server project
http://www.linuxvirtualserver.org
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