[DRBD-user] Directly connected GigE ports bonded together no switch

Andreas Hofmeister andi at collax.com
Wed Aug 10 19:28:57 CEST 2011

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

On 10.08.2011 19:04, Herman wrote:
> If this is the case, maybe arp monitoring is more reliable for direct
> connections since NIC failure (which may fail but still have link up) is
> more likely than cable failure?  Maybe I don't have a good understanding
> of this.

With switches in between, ARP monitoring is a bit dangerous because you 
either need a switch that answers the ARP queries (i.e it must be 
manageable) or you have another machine that answers. But then what 
happens when that other machine is down ...

With direct connections between hosts this does not matter though - 
whether the other side does not answer due to a broken cable, an 
exploded NIC or just plain reboot is just the same.

> In addition, I tried to use scp to test the throughput through the
> bonded link, but I actually got almost the same results via
> active-backup as with balance-rr.  Am I doing something wrong?

With SSH you will see basically the rate at which the hosts can 
en-/decrypt packets. Better try something like "iperf" or some file 
server that does not encrypt traffic, NFS or FTP for example.


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