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Thanks for your quick response.
On Thu, Mar 8, 2012 at 5:33 PM, Michael Schwartzkopff <
misch@xxxxxxxxxxxxxxxxx> wrote:
> > Hello all,
> >
> > I am running pulse on virtual machine for webserver, it seems working
> > well, but there is one problem with networking I think. It seems there
> > is a problem with lvs server is not fragmenting larger than 1500
> > packets size. I did the quick tcpdump and I get following info.
> >
> > my problem is when user is uploading files it takes for ever and never
> > completes. I am thinking lvs (pulse) is not not fragmenting the larger
> > packet size than 1500 hence it never goes to backend server.
> >
> > 16:25:22.543563 00:1f:6d:cf:4e:49 > 52:54:00:b5:30:3c, ethertype IPv4
> > (0x0800), length 2974: 10.128.1.5.60715 > 10.192.6.1.https: Flags [.],
> > seq 7705:10625, ack 146, win 16388, length 2920
> > 16:25:22.543590 52:54:00:b5:30:3c > 00:1f:6d:cf:4e:49, ethertype IPv4
> > (0x0800), length 590: 10.192.6.1 > 10.128.1.5: ICMP 130.208.165.177
> > unreachable - need to frag (mtu 1500), length 556
> >
> > I tested following:
> >
> > 1. IP forward is enabled.
> > 2. lro,gro are off on eth0
> > ethtool -k eth0
> > Offload parameters for eth0:
> > rx-checksumming: on
> > tx-checksumming: on
> > scatter-gather: on
> > tcp-segmentation-offload: on
> > udp-fragmentation-offload: on
> > generic-segmentation-offload: on
> > generic-receive-offload: off
> > large-receive-offload: off
> > 3. IPVS version is v1.2.1
> > 4. Backend server has arptables and set to mangaled to right interface
> > 5. Firewall is allowed on both lvs and backend server.
> > 6. http and https are open for all.
> >
> > Any help in this would be great.
>
> It seems that the LVS cannot send out the packet since the MTU is too large
> for the 1500 Byte of the interface. Please don't be confused by the length
> of
> 2974 byte that tcpdump shows. tcpdump just sees the packet on the wrong
> point
> on the chain.
>
> I see, how tcpdump reference length 2974 byte ? I was trying to understand
this length and concluded it is something problem with lvs.
> Be sure the Path MTU discovery works or clear the DF bit of the packet
> entering the load balancer.
>
> how do I check this, or is there a way to tell lvs to if the packet size
is larger then force to defrag ? Perhaps this should be handed in linux
kernel ? I am using redhat 6.2
> Greetings,
>
>
> --
> Dr. Michael Schwartzkopff
> Guardinistr. 63
> 81375 München
>
> Tel: (0163) 172 50 98
> Fax: (089) 620 304 13
>
> _______________________________________________
> Please read the documentation before posting - it's available at:
> http://www.linuxvirtualserver.org/
>
> LinuxVirtualServer.org mailing list - lvs-users@xxxxxxxxxxxxxxxxxxxxxx
> Send requests to lvs-users-request@xxxxxxxxxxxxxxxxxxxxxx
> or go to http://lists.graemef.net/mailman/listinfo/lvs-users
>
_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/
LinuxVirtualServer.org mailing list - lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Send requests to lvs-users-request@xxxxxxxxxxxxxxxxxxxxxx
or go to http://lists.graemef.net/mailman/listinfo/lvs-users
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