Thanks for your quick response. On Thu, Mar 8, 2012 at 5:33 PM, Michael Schwartzkopff < [email protected]> 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 - [email protected] > Send requests to [email protected] > 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 - [email protected] Send requests to [email protected] or go to http://lists.graemef.net/mailman/listinfo/lvs-users
