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Re: single cable dual nic?

On 25 April 2011 09:32, Henrique de Moraes Holschuh <hmh@debian.org> wrote:
> On Sun, 24 Apr 2011, Jim Green wrote:
>> I have a asus p8p67 deluxe board and it has two nics and two ports, I
>> am thinking of bonding them to one nic, but I only have one cable so
>> will only use one port. Will this do much help to the
>> throughput/speed? If I have two cables connecting to both ports I
>> think it will definitely help, but here I only be using one cable/one
>> port and two nics bonded to one virtual nic.
> Your board has Realtek 8111Es for NICs.  I won't sugar-coat it: that
> stuff cannot be called good gigabit ethernet NICs in any way.  Its only
> saving grace is that it is dirty cheap.
> Try to get jumbo frames working on your network, it should help you get
> better throughput _if it works right_.  You just have to set the MTU to
> the *same jumbo frame size* on *every host on your network* to enable
> that.  But make sure your switch can handle jumbo frames first, and that
> such support is enabled.
> Example jumbo MTU sizes: 9000, 7200, 4000.  Which one you can reliably
> use depends on the least capable device in your network and their bugs.
> I would expect bonding to actually make things worse with r8169-based
> NICs, but maybe it would distribute the interrupts better and give you
> better performance at the cost of wasting even more CPU resources.  This
> is only cost-effective if you happen to have a gigabit managed switch
> capable of link bonding (LACP) already, or when directly connecting two
> computers.
> Bonding with just one cable simply doesn't help performance.  Either the
> devices notice the missing link and disable the offending ports (and you'll
> be slightly worse off than you'd be without any bonding in the first place),
> or you will have the packet loss from hell.

Looking at this, I think I am better off disabling the realtec nic and
use intel® 82579 Gigabit LAN controller on the board instead.


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