Re: [lvs-users] Some users slow loading..

To: lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Subject: Re: [lvs-users] Some users slow loading..
From: Joerg Delker <jd_lvs@xxxxxxx>
Date: Fri, 14 Sep 2007 18:18:14 +0200
Hi Folks,

I just found this thread in the archives describing my problem.
So let me tune in so we hopefully can find that bummer.

I'm also suffering from very slow connections via the VIPs in contrast to accessing the real servers directly. A wget fetch from a particular web takes ~40sec via the VIP and ~4sec directly.

Looking at the related tcpdumps for the VIP traffic I see:
in dump (Client<->Director):
  * TCP Retransmissions VIP->Client
  * Duplicate ACKs Client->VIP
in dump (Director<->Realserver)
  * TCP Retransmissions Realserver->Client
  * Duplicate ACKs Client->Realserver
  * TCP previous segment lost Client->Realserver (appears after each Dup ACK)

Note: Routing client traffic directly to the real server shows perfect TCP traffic!

The director is acting as firewall, router, loadbalancer using
ipvsadm v1.24 2003/06/07 (compiled with popt and IPVS v1.2.0)
and configured as LVS-NAT to access the real servers.
Kernel tested: 2.6.16, 2.6.18, 2.6.22 - no difference noticable
Hardware issues can be ruled out as the directly routed traffic uses exact the same path.

Any hints welcome!


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