LVS
lvs-users
Google
 
Web LinuxVirtualServer.org

Re: IMAP and LVS problems

To: lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Subject: Re: IMAP and LVS problems
From: Ramon Kagan <rkagan@xxxxxxxx>
Date: Wed, 27 Nov 2002 13:54:40 -0500 (EST)
HI,

Further update on the solution.

although this works there is one catch.  If a person logs out and comes
back within the 7200s as stated in the previous email, they continue to
get the message because the real server and the director don't match
again.  We will be lowering the value to somewhere between 5 and 15
minutes (300-900) to address this type of usage.

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 Fri, 22 Nov 2002, Ramon Kagan wrote:

> HI,
>
> Thank you for your suggestions.  The solution:
>
> On the linux imap servers the tcp-keepalive value in
>
> /proc/sys/net/ipv4/tcp_keepalive_time is set to 7200
>
> centaur# pwd
> /proc/sys/net/ipv4
> centaur# cat tcp_keepalive_time
> 7200
>
> This must be matched by the ipvsadm tcp timeout.  So the options are to:
>
> 1.  use ipvsadm --set 7200 0 0 on the lvs server
> or
> 2.  echo "900" >! /proc/sys/net/ipv4/tcp_keepalive_time
>
> Either of these work.  I have not had any further problems with this since
> I made the changes.  Maybe this could be appended to the TCP timeout issue
> in the FAQ/DOCs for IMAP for future reference.
>
> Thanks again for you help,
>
> 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:
> >
> > > > 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
> >
> > maybe it's the LVS timeout. There is also a tcp keepalive timeout somewhere 
> > too
> > which is separate from the LVS timeout.
> >
> > > The tcp connections go through the normal cycle, EST, WAIT, FIN_WAIT...
> >
> > does the client disconnect between fetches or is the connection open all 
> > the time?
> >
> > does the client maintain a (possibly separate)
> > connection to the demon to keep authentication valid?
> >
> > > However the imap daemon is kept alive, and the client is shipped the PID
> > > of the imapd to reconnect directly.
> >
> > didn't know you could connect to a process number on a remote machine ;=\
> >
> > 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
> >
>
>
> _______________________________________________
> 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
>



<Prev in Thread] Current Thread [Next in Thread>