Re: Pirana problem with MTU fragmentation

Andrey Feldman <[email protected]> Thu, 08 Mar 2012 23:03:20 +0400
Newsgroups gmane.linux.redhat.piranha
Message-ID <[email protected]> 
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Hi.
cat /proc/sys/net/ipv4/ip_no_pmtu_disc ?
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 00:1f: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  <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
>
>
> _______________________________________________
> Piranha-list mailing list
> [email protected]
> https://www.redhat.com/mailman/listinfo/piranha-list


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    Hi.<br>
    cat /proc/sys/net/ipv4/ip_no_pmtu_disc ?<br>
    tracepath 10.192.6.1 ?<br>
    ifconfig -a ?<br>
    <br>
    On 03/08/2012 07:29 PM, Khapare Joshi wrote:
    <blockquote
cite="mid:CABHhH+uQoDhm3K9vqCjDX8FUEz-a1=WG8EoqfhQF-4TUhZ88_w@mail.gmail.com"
      type="cite">
      <pre>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 &gt; 52:54:00:b5:30:3c, ethertype IPv4 (0x0800), length 2974: 10.128.1.5.60715 &gt; 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 &gt; 00:1f:6d:cf:4e:49, ethertype IPv4 (0x0800), length 590: 10.192.6.1 &gt; <a moz-do-not-send="true" href="http://10.128.1.5">10.128.1.5</a>: 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</pre>
      <br>
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      <br>
      <pre wrap="">_______________________________________________
Piranha-list mailing list
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<a class="moz-txt-link-freetext" href="https://www.redhat.com/mailman/listinfo/piranha-list">https://www.redhat.com/mailman/listinfo/piranha-list</a></pre>
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_______________________________________________
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