Pirana problem with MTU fragmentation

[Andrey Feldman]

Ok, and the other stuff too:
tracepath 10.192.6.1 ?
ifconfig -a ?

In other words - i think problem is not in LVS, but in networking.
Maybe it's better to turn on jumbos on all sides: VMware host, switches, 
LVS-director, Real server?
Or turn it off everywhere.


On 03/08/2012 11:08 PM, Khapare Joshi wrote:
> Hi Andrey
>
> On Thu, Mar 8, 2012 at 7:03 PM, Andrey Feldman <pr1 at pr1.ru 
> <mailto:pr1 at pr1.ru>> wrote:
>
>     Hi.
>     cat /proc/sys/net/ipv4/ip_no_pmtu_disc ?
>
>
>  cat /proc/sys/net/ipv4/ip_no_pmtu_disc
> 0
>
>     tracepath 10.192.6.1 ?
>     ifconfig -a ?
>
>
>     On 03/08/2012 07:29 PM, Khapare Joshi 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  <tel:22.543563%2000>: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  <tel:22.543590%2052>:54:00:b5:30:3c>  00:1f:6d:cf:4e:49, ethertype IPv4 (0x0800), length 590: 10.192.6.1>  10.128.1.5  <http://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.
>>
>>     K
>>
>>
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