|
HI,
see below
Thanks,
Ramon Kagan
York University, Computing and Network Services
Unix Team - Intermediate System Administrator
(416)736-2100 #20263
rkagan@xxxxxxxx
-------------------------------------
I have not failed. I have just
found 10,000 ways that don't work.
- Thomas Edison
-------------------------------------
On Wed, 20 Nov 2002, Joseph Mack wrote:
> Ramon Kagan wrote:
> >
> > HI,
> >
> > Linux 2.4.18
> > IPVS 1.0.4
> >
> > Previously we had been using DNS shuffle records to spread the load of
> > IMAP connections across 3 machines. Having used LVS for web traffic for a
> > long time now (about 2.5 yeras) we decided to bring our IMAP service into
> > the pool. The imap servers have been setup to retain idle connections for
> > 24 hours (not my choice but the current setup anyways). The lvs servers
> > have
> > been setup to have a persistance of 8 hours. What has been happening
> > lately is that users get the following type error.
>
> is "lately"
>
> o after you moved IMAP to LVS
> o something else
>
BTW forgot to say that I'm using DR
after I moved IMAP to LVS
> > "The server has disconnected, may have gone down or may be a network
> > problem, try connecting again"
>
> is this after 8hrs, 24hrs, or something else?
>
actually just about anything, as low as ten minutes, and those are the
ones I really worry about
> > So, users don't have to reauthenticate per se, they just need to reclick
> > on whatever button, so that the client they are using reauthenticates
> > them.
> >
> > Anybody have ideas on what is happening, this didn't occur prior to going
> > to LVS.
>
> I don't know how IMAP works -
>
> does it keep a tcp connection open all the time or is each fetch a new
> connection?
>
The tcp connections go through the normal cycle, EST, WAIT, FIN_WAIT...
However the imap daemon is kept alive, and the client is shipped the PID
of the imapd to reconnect directly. This is supposed to circumvent the
necessity of reauthentication. In the case where the connection is lost,
the reauthentication actually starts a new imapd process.
> How is the state of authentication maintained between fetches?
>
> there is a tcp timeout associated with tcp connections through LVS which
> affects telnet, ssh sessions.
>
I'll try setting the value to 8 hours like the persistence value.
> http://www.linuxvirtualserver.org/Joseph.Mack/HOWTO/LVS-HOWTO.services.html#timeout
>
> Joe
>
> --
> Joseph Mack PhD, Senior Systems Engineer, SAIC contractor
> to the National Environmental Supercomputer Center,
> mailto:mack.joseph@xxxxxxx ph# 919-541-0007, RTP, NC, USA
>
> _______________________________________________
> LinuxVirtualServer.org mailing list - lvs-users@xxxxxxxxxxxxxxxxxxxxxx
> Send requests to lvs-users-request@xxxxxxxxxxxxxxxxxxxxxx
> or go to http://www.in-addr.de/mailman/listinfo/lvs-users
>
|
