[DRBD-user] Supported bonding modes for drbd interconnect

Digimer lists at alteeve.ca
Sat Sep 28 00:44:34 CEST 2013

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On 27/09/13 15:32, Arnold Krille wrote:
> Hi,
> On Thu, 26 Sep 2013 08:33:02 +0000 Andreas Mock 
> <andreas.mock at drumedar.de> wrote:
>> I couldn't find a definitiv answer for my question: Which 
>> ethernet bonding modes are supported for the DRBD interconnect?
>> I found the following in 
>> http://www.drbd.org/users-guide-8.4/s-prepare-network.html
>> "[...] and the bonding driver (in active-backup mode) is
>> recommended [...]" Does this mean: When you use the recommended
>> bonding than you HAVE to use active-passive?
> I did some experiments with bonding two 1G links. As expected 
> active-passive gives you fallback even when the two links go from 
> machine to two (interconnected) switches. With that you can wire 
> both nodes to both switches, interconnect the switches and get a 
> setup the works even if one switch or one cable stops working. 
> balance-rr only works on directly connected machine, switches get 
> confused about the mac-addresses hopping between ports. And then 
> your switches are so busy updating their arp-tables that they
> can't route the data anymore. When you really want to use two links
> from machine to switch to machine, you have to use LACP so each 
> component knows what to do.
> In the end I stopped my experiments and choose active-passive 
> bonding across two switches for the main interface and balance-rr 
> for the direct 2x10G-link. Now its up to the various
> drbd-resources (~20 on last count) to max out 20G bandwidth.
> Hope that helps.
> Have fun,
> Arnold

In my testing, I found the same. Only mode=1 was reliable in all
failure and recovery scenarios I tested. If you choose any other mode,
be sure to test the failure and recovery of links and switches.

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