[DRBD-user] bond for drbd identical performance with one link down

Bart Coninckx bart.coninckx at telenet.be
Thu May 20 20:24:00 CEST 2010

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


On Thursday 20 May 2010 20:15:36 Lee Riemer wrote:
> Do you need multiple destination IPs to properly balance?  It is my
> understanding that a single stream will only traverse a single link.
> Hence the MPIO requirement.
> 
> On 5/20/2010 1:07 PM, Bart Coninckx wrote:
> > Hi,
> >
> > Admittedly  not a DRBD issue per se, but I guess this list represents
> > quite some experience in the area: I have two gigabit NICs bonded in
> > balance-rr mode for DRBD sync. They are directly linked (no switch) to
> > the other other pair in the other DRBD node.
> >
> > Before syncing things I was testing the performance and failover. Netperf
> > shows for instance this:
> >
> >
> > iscsi2:/etc/sysconfig/network # netperf -p 2222 -H 10.0.2.3
> > TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.0.2.3
> > (10.0.2.3) port 0 AF_INET
> > Recv   Send    Send
> > Socket Socket  Message  Elapsed
> > Size   Size    Size     Time     Throughput
> > bytes  bytes   bytes    secs.    10^6bits/sec
> >
> >   87380  16384  16384    10.00     977.83
> >
> >
> > Pulling one cable gives me about the same speed. I would expect it to be
> > at least 20% slower. It seems the round robin does not speed up things.
> >
> > The bonds on both sides show up fine in /proc/net/bonding/bond0.
> >
> > Anyone any idea what I'm doing wrong?
> >
> > Cheers,
> >
> >
> > Bart
> > _______________________________________________
> > drbd-user mailing list
> > drbd-user at lists.linbit.com
> > http://lists.linbit.com/mailman/listinfo/drbd-user
> 
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Lee,

do I understand you correctly that the speed gain will only be noticeable with 
balance-rr when I have multiple IP's on the destination bonding interface? If 
so, how does DRBD benefit from this? I can only set one IP address for a 
resource (or at least so I believed).

Cheers,

Bart



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