Re: [Zenloadbalancer-support] weird mtu issue

[Emilio C. <emi...@gm...>]

Hi Matt, thanks for your report, personally I experienced issues with
offloading in nic drivers, by default the recommended option is disable
this, to keep these parameters as permanent please enter your command in
the script /usr/local/zenloadbalancer/config/zlb-start  in your favorite
language. This script will be executed after the zen  process start
concludes.

Regards

2015-08-02 15:15 GMT+02:00 Mathieu Chateau <mat...@lo...>:

> Hello,
>
> I have a weird behavior and found solution that may interest others
>
> Context:
>
>    - All servers are VM under VMware ESXi 5.5, even ZLB
>    - All VM having VMXnet 3 virtual nic
>
> issue:
> When doing L4xnat, With one frontend server, badnwidth is terribly slow.
> It's FTP service that is used. I am the only one, copying 1 big file.
>
> As soon as I start, ZLB keep sending ICMP packets to the FTP server:
> 14:45:54.829302 IP ZLBIPADDR > FTPSERVER: ICMP
> prd-sta-slb01.intern.mobistep.net unreachable - need to frag (mtu 1500),
> length 556
>
> I checked everywhere, MTU is 1500.
>
> Now If I put the second FTP server, which is even accross a vpn, then no
> ICMP, and great bandwidth (11MB/s instead of 40KB/s)
>
>
> These 2 FTP servers are also Web server, load balancer through the same
> ZLB as web farm, not a single ICMP message.
>
> After digging with Wireshark, yes the slow one is sending packet bigger
> than MTU. This server is on same vswitch as ZLB internal card.
>
> It appeard that VMware nic do offloading and so then bigger packet than
> MTU.
>
> Everything is ok as soon as I disable TCP offloading on FTP server:
>
> *ethtool -K ens160 tx off sg off tso off*
>
> Maybe someone have a better config on ZLB to avoid that?
>
>
> Regards,
> Mathieu CHATEAU
> http://www.lotp.fr
>
>
> ------------------------------------------------------------------------------
>
> _______________________________________________
> Zenloadbalancer-support mailing list
> Zen...@li...
> https://lists.sourceforge.net/lists/listinfo/zenloadbalancer-support
>
>


-- 
Load balancer distribution - Open Source Project
http://www.zenloadbalancer.com
Distribution list (subscribe): zen...@li...