could it be due to i install on virtual server which mean network interface is shared - is that could be a bottleneck ? I am not sure how to debug this further.
K On Thu, Mar 8, 2012 at 7:05 PM, Khapare Joshi <[email protected]> wrote: > 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
