You can also not use your seat belt and tear down the highway. Doesn't mean it is a good idea.
If you don't use proper fencing, you WILL run into trouble. When that happens, don't blame the software. You've been told directly and plainly that you *must* use fencing. If you don't, you will have a split-brain and it will be an avoidable disaster. Why not just use fencing? digimer On 13/05/15 03:43 AM, DRBD User wrote: > found a way without fencing: > > create /etc/dlm/dlm.conf and copy to all nodes > > * To use no fencing, use this line: > > enable_fencing=0 > > > > now if i pull the power plug it takes about 5sec and the other node continue > to operate > > > Gesendet: Mittwoch, 13. Mai 2015 um 09:29 Uhr > Von: "DRBD User" <[email protected]> > An: [email protected] > Betreff: [DRBD-user] Dual Primary Mode: Shared Directory blocked after node > crash until reboot > for manual ack i use these (RHEL7) : > > dlm_tool fence_ack nodeid > > > > Gesendet: Mittwoch, 13. Mai 2015 um 09:23 Uhr > Von: Digimer <[email protected]> > An: "DRBD User" <[email protected]>, [email protected] > Betreff: Re: [DRBD-user] Dual Primary Mode: Shared Directory blocked after > node crash until reboot > If you want automatic recovery of any sort, yes, it is required to avoid > a split brain. > > On 13/05/15 03:00 AM, DRBD User wrote: >> So for a primary/secondary setup I have to deal with fencing/stonith too ? >> >> I am using RHEL 7 and i can't find the fence_ack_manual command (for test >> purposes) ? >> >> >> >> Gesendet: Mittwoch, 13. Mai 2015 um 08:40 Uhr >> Von: Digimer <[email protected]> >> An: "DRBD User" <[email protected]>, [email protected] >> Betreff: Re: [DRBD-user] Dual Primary Mode: Shared Directory blocked after >> node crash until reboot >> On 13/05/15 02:36 AM, DRBD User wrote: >>> Ok i understand: >>> >>> In a dual primary setup without a valid stonith configuration i have to >>> wait until the crashed node is set to a *known* state: eg. using reboot, >>> manual intervention. >>> >>> But what if the crashed node never gets alive: >>> Will the stonith setup set the state of the crashed node to a *known* >>> state, so that the active node can continue to operate ? >>> Or do I have to intervene manually ? >>> >>> So for my plan to have a high available service (which saves its state to a >>> shared directory) a primary/secondary setup may be the way to go - or i is >>> fencing/stonith always a must ? >> >> The cluster (and DRBD) will remain blocked indefinitely. The only way to >> resume operation is when fencing succeeds or a human tells DRBD that the >> lost node is offline (via manual intervention). >> >> As an aside; Red Hat used to support manual fencing, but dropped support >> for it when RHEL 6 was released in 2010. The reason was that, on paper, >> manual fencing sounds fine. In practice, it was often misused and lead >> to split-brains. >> >> Consider; A cluster is locked up, people are screaming and the poor >> admin is trying to remember what to after a year of not touching things. >> s/he remembers about manually clearing the fence and then does so >> without first verifying the last node was off/dead. Is such a case, you >> have a split-brain and all the potential damage that goes with it. >> >> Get hardware fencing. It is the only sane and sensible option. >> >> -- >> Digimer >> Papers and Projects: https://alteeve.ca/w/ >> What if the cure for cancer is trapped in the mind of a person without >> access to education? >> _______________________________________________ >> drbd-user mailing list >> [email protected] >> http://lists.linbit.com/mailman/listinfo/drbd-user[http://lists.linbit.com/mailman/listinfo/drbd-user][http://lists.linbit.com/mailman/listinfo/drbd-user[http://lists.linbit.com/mailman/listinfo/drbd-user]][http://lists.linbit.com/mailman/listinfo/drbd-user[http://lists.linbit.com/mailman/listinfo/drbd-user][http://lists.linbit.com/mailman/listinfo/drbd-user[http://lists.linbit.com/mailman/listinfo/drbd-user]]] >> _______________________________________________ >> drbd-user mailing list >> [email protected] >> http://lists.linbit.com/mailman/listinfo/drbd-user[http://lists.linbit.com/mailman/listinfo/drbd-user][http://lists.linbit.com/mailman/listinfo/drbd-user[http://lists.linbit.com/mailman/listinfo/drbd-user]] >> > > > -- > Digimer > Papers and Projects: > https://alteeve.ca/w/[https://alteeve.ca/w/][https://alteeve.ca/w/[https://alteeve.ca/w/]] > What if the cure for cancer is trapped in the mind of a person without > access to education? > _______________________________________________ > drbd-user mailing list > [email protected] > http://lists.linbit.com/mailman/listinfo/drbd-user[http://lists.linbit.com/mailman/listinfo/drbd-user] > _______________________________________________ > drbd-user mailing list > [email protected] > http://lists.linbit.com/mailman/listinfo/drbd-user > -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education? _______________________________________________ drbd-user mailing list [email protected] http://lists.linbit.com/mailman/listinfo/drbd-user
