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Re: [lvs-users] TCP Retransmissions?

To: <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] TCP Retransmissions?
From: housey@xxxxxxxxxxxxxx
Date: Thu, 27 Jun 2013 16:09:38 +0100
Hi Daryl

Its a Virtual Machine running on esxi 4.1 using VMXNET 3 as the network 
adaptor.

The physical machine is a dell 1950 which does have broadcom network 
adaptors.

Is there anything I need to take account of running LVS on esxi?

Thanks

Paul


On 27.06.2013 13:28, daryl herzmann wrote:
> Hi,
>
> Is this a bnx2 card?  Try disabling GRO for both devices
>
> ethtool -K eth0 gro off
> ethtool -K eth1 gro off
>
> daryl
>
> On Wed, 26 Jun 2013, housey@xxxxxxxxxxxxxx wrote:
>
>> Hi
>>
>> Ive been looking into LVS to help balance load amongst some SMTP
>> servers.
>>
>> I have set up a test LVS system in front of 3 real SMTP servers.
>>
>> I'm using direct routing and have used the iptables method on all 3
>> real servers to overcome any arp issues
>>
>> i.e. iptables -t nat -A PREROUTING -p tcp -d <vip> --dport 25 -j
>> REDIRECT
>>
>> My testing seems to be going well and I can see traffic being 
>> balanced
>> between the 3 servers, however I ran tcpdump on the lvs server just 
>> to
>> look at the traffic and noticed im getting lots of TCP 
>> Retransmission
>> and some TCP Dup ACK's
>>
>> I ran tcpdump on a normal SMTP server and don't see anywhere near as
>> many.
>>
>> Can someone lend me their experience and advise if this something I
>> need to worry about and investigate further?
>>
>> Thanks
>>
>> Paul
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> Please read the documentation before posting - it's available at:
>> http://www.linuxvirtualserver.org/
>>
>> LinuxVirtualServer.org mailing list - 
>> lvs-users@xxxxxxxxxxxxxxxxxxxxxx
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>>


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