Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 2008-09-15T08:28:18, Lars Ellenberg <lars.ellenberg at linbit.com> wrote: > > > > The restart of the secondary is not just "spurious" though. It might > > > > actually help "fix" (or at least "reset") things. Restarts are amazingly > > > > simple and effective. > > > hmm. > > You've got to admit that it's a valid point ;-) > that was more a disagreeing grumble. > it may also break things. How so? > if we set aside confused admins for the moment, > and assume CRM is the only entity promoting/demoting drbd. > > would it not be enough for a Primary on connection loss to > set some constraint pinning the master role on that node/node group? > > the DRBD after-resync handler can then remove that contraint again. The idea is interesting. A RA modifying its own constraints ... However, it wouldn't work for a true split-brain. If the primary does that before being fenced by the secondary (which, given awkward circumstances for the split-brain, is possible), and the partition heals, the master would be pinned to the "wrong" node briefly. Also, given that it is a split-brain and the constraint is only on one side, the secondary would allow itself to be promoted - okay, so the cluster never would before the primary has been fenced, but neither must the master continue before the secondary has been fenced ... Does that make sense? Regards, Lars -- Teamlead Kernel, SuSE Labs, Research and Development SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg) "Experience is the name everyone gives to their mistakes." -- Oscar Wilde