[DRBD-user] DRBD: failover when sync connection dies?

Lars Ellenberg lars.ellenberg at linbit.com
Tue Dec 18 15:52:44 CET 2007

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

On Mon, Dec 17, 2007 at 10:55:02AM +0100, Martin Gombac wrote:
> On 2007.12.13, at 18:24, Martin Gombac wrote:
> >On 2007.12.13, at 17:42, Florian Haas wrote:
> >
> >>On Thursday 13 December 2007 13:45:47 Martin Gombac wrote:
> >>>Hi,
> >>>
> >>>i have a simple fail-over heartbeat/drbd cluster set up. In each
> >>>server there are two network cards. One for internet access (WAN)  
> >>>and one for internal communication and synchronization (LAN). If
> >>>one  node looses internet connection (WAN) the other takes over all
> >>>resources as expected, but this does no thappen with local
> >>>connection (LAN) which is just crossover UTP cable.
> >>>In case if local connection (LAN) fails, cluster does not migrate
> >>>all resources to one of the nodes and just continues to work
> >>>without synchronized drbd resources (amongst other things).
> >>>
> >>>My question is this:
> >>>How can i make one node take over all resources if local crossover

you don't want to.

if your lan connection dies,
and your lan connection was your replication link,
then you don't have replication anymore,
and so you would go online with non-current data.

if currently your LAN connection is a direct "crossover cable",
why would you think any clients would benefit from failing over?

if you change to a switched LAN, and add a ping node,
why do you think any clients would benefit from that?

how can you be sure what component failed,
 local NIC, cables, remote NIC, switch, driver, ...?

what problem are you trying to solve?
  I mean not "failing over when the LAN link dies".
  please zoom out a little.

from my point of view, it makes no sense to trigger a failover
because the replication link dies. it would even be harmful.
so don't do that.

: Lars Ellenberg                           http://www.linbit.com :
: DRBD/HA support and consulting             sales at linbit.com :
: LINBIT Information Technologies GmbH      Tel +43-1-8178292-0  :
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