[DRBD-user] Broken connection when drbd starts the sync

Daniel van Ham Colchete daniel.colchete at gmail.com
Sat Dec 9 05:48:38 CET 2006

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


Balázs,

looking at DRBD's code I found that the 'magic??' line means that the
secondary node received an incorrect packet, the packet's header is
incorrect (invalid magic code). Think you magic as the "first bytes of
something".

Try the following (in that order):
1 - Disable jumbo packets if enabled. If not, try a small MTU setting
on both nodes. If it doesn't solve the issue, them enable the jumbo
packets, try putting a MTU of 5000 bytes. Playing with the MTU setting
helps to understand why would you have incorrect packets in your
traffic. It may be an ethernet problem, them setting a small MTU helps
to solve it. It also might be a fragmentation problem, them increasing
the MTU helps to solve it.

2 - Upgrade DRBD to 0.7.22. Everything before it has a serious bug
with the A and B protocols that might result in data loss.

At least you know where the problem is: the "magic??" matter..

Best regards,
Daniel Colchete

On 12/8/06, Zachár Balázs <zachar at direkt-kfki.hu> wrote:
> Firstly, Thx for the answer, I searched program like this many times but
> I never found! So now, I am happy! :)
>
>
> Secondly, I run the tests but they were successfully! I run it for 30
> sec and 600 sec (the correct form for the time limit: iperf -c node1 -t
> 30) but both test were right!
>
> There isn't firewall on these nodes yet.
>
> Another idea?
>
> Regards,
> Balázs
>
> Daniel van Ham Colchete írta:
> > Balázs,
> >
> > if I were you I would first test my network conection on intensive
> > traffic.
> >
> > Try using IPERF (http://dast.nlanr.net/Projects/Iperf/). Start iperf
> > with "iperf -s" at the first node a them "iperf -c node1 -s 30" on the
> > second. If everything goes OK, them increase the test time (-s 30 = 30
> > seconds).
> >
> > This will tell you if your having any problems with the
> > driver/kernel/NIC/cable systems. You could also check your firewall
> > rules for any climit/limit rule.
> >
> > Best regards,
> > Daniel Colchete
> >
> > On 12/8/06, Zachár Balázs <zachar at direkt-kfki.hu> wrote:
> >> Hello @list!
> >>
> >>
> >> I use drbd 0.7.21 on SUSE prof 10.1.
> >>
> >> I configured it and when I starting the drbd, everything looks fine, but
> >> when It starting to sync it works fine about 10 sec and then crash.
> >>
> >> Between the two PC I use Cat 6 cross 1000 Mb/s cable.
> >>
> >> Before the crash I can ping the onother node on the drbd interface but
> >> after the crash I can't!!! And there isn't any link down message in the
> >> logs.
> >>
> >> What is it mean magic?? in the B-node's log???
> >>
> >> Thanks,
> >> Balázs
> > _______________________________________________
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> > drbd-user at lists.linbit.com
> > http://lists.linbit.com/mailman/listinfo/drbd-user
> >
> >
> >
>
>
>
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