[Drbd-dev] Another drbd race

Lars Ellenberg lars.ellenberg at linbit.com
Wed Sep 8 13:31:10 CEST 2004

On Wed, Sep 08, 2004 at 01:20:01PM +0200, Lars Marowsky-Bree wrote:
> On 2004-09-07T14:47:45,
>    Philipp Reisner <philipp.reisner at linbit.com> said:
> > No. It would be better to have a "drbdadm fence r0" operation on N2!
> > The "drbdadm fence r0" command would only set the "Outdated" flag.
> Well, it's automatically supposed to assume it's outdated when it
> crashes in S-P mode.
> When the secondary loses connection to the primary, a mark-peer-dead
> would prevent that flag from being set.
> So, why an explicit drbdadm fence operation? I'm missing what that would
> catch.

we probably can cope without, but it is more "polite" if we have it.
if we _can_ handle it explicit, why not?
implicit things are more easy to overlook...

  P --- S  
  P xxx S        link breaks

  [ you can insert here even a complete cluster crash ]

  X xxx S        N2 receives "Peer dead", but still is outdated.

  the point is: just receiving a "peer definetely dead" in S/?
  is not enough to know that we are not outdated.


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