[DRBD-user] GigE vs Bonded NICs

CA Lists lists at creativeanvil.com
Thu Jul 5 18:19:44 CEST 2007


Graham Wood wrote:
>
>> My thought was that this may degrade the reliability of DRBD by it 
>> not having its own private communication channel.
> If you were to bond the NICs, then there is certainly the possibility 
> that other network access to the server could flood the network.  
> However, it's unlikely that enough data could be thrown at them to 
> flood a 2Gbps connection.
>
> Other problems relate to the data going out on the "public" network, 
> and the possibility of an IP conflict causing other problems (e.g. if 
> a 3rd machine on the network accidentally, or on purpose if someone 
> was trying to "attack" your storage, was set to the same IP as one of 
> the nodes).
Well, everything that has access to these servers is on the 
192.168.1.0/24 network, and I'm the only one with any access, so, 
something coming up on the same IP is possible, but unlikely. Good point 
though.
>
>> Or is bonding everything together so that it all can run at 2Gbps a 
>> good idea?
> The extra bandwidth is only relevant if you are seeing a bottleneck 
> within your system.  If the filesystem is working well without any 
> delays, then the additional bandwidth is not that relevant.  The main 
> advantage of bonding the interfaces would be the increased redundancy. 
>  By the sound of it, your system has single connections between each 
> device in the environment - which means that a single NIC/cable 
> failure could cause one of the servers to disappear.
>
> Personally I think the best answer would be to bond the interfaces 
> (dual active), and then use VLANs on top to keep the traffic 
> segregated.  This gives you the additional redundancy and bandwidth, 
> as well as still keeping the internal data separate from public data 
> to prevent the accidents/attacks discussed above.  The downside to 
> this is that the switches would need to support it - and if you want 
> to keep the networking redundant you would need a pair of pretty 
> recent switches to support the dual active functionality - since with 
> so few nodes involved, the various methods that don't need switch 
> support probably wouldn't help much.
Yeah, one of the big benefits I saw to it was the redundancy it offered. 
Thanks for the info.

Also, someone earlier asked if the disks could keep up with the 2Gbps - 
from running hdparm -tT, it would appear they can outperform 1Gbps by 
just a little, but could not keep up with 2Gbps. Again, I was very 
interested in the redundancy offered, as well as the potential for a bit 
more speed, but didn't want to have issues with too much different 
traffic on the network.

Thanks again to all that responded.



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