[ClusterLabs] Antw: Re: Any CLVM/DLM users around?

Ulrich Windl Ulrich.Windl at rz.uni-regensburg.de
Mon Oct 1 15:47:17 EDT 2018


Maybe explain how your "node failed": Usually when I node has failed, fencing is just to make sure that the node is really dead, so in most cases it won't actually do a thing unless a false "node dead" had been detected. Fencing makes sure that the fenced node has absolutely no chance to access shared storage until it joined the cluster again (after reboot).


>>> Patrick Whitney <pwhitney at luminoso.com> 01.10.18 19.44 Uhr >>>
We tested with both, and experienced the same behavior using both fencing
strategies:  an abandoned DLM lockspace.   More than once, within this
forum, I've heard that DLM only supports power fencing, but without
explanation.  Can you explain why DLM requires power fencing?


On Mon, Oct 1, 2018 at 1:38 PM Vladislav Bogdanov <bubble at hoster-ok.com>

> On October 1, 2018 4:55:07 PM UTC, Patrick Whitney <pwhitney at luminoso.com>
> wrote:
> >>
> >> Fencing in clustering is always required, but unlike pacemaker that
> >lets
> >> you turn it off and take your chances, DLM doesn't.
> >
> >
> >As a matter of fact, DLM has a setting "enable_fencing=0|1" for what
> >that's
> >worth.
> >
> >
> >> You must have
> >> working fencing for DLM (and anything using it) to function
> >correctly.
> >>
> >
> >We do have fencing enabled in the cluster; we've tested both node level
> >fencing and resource fencing; DLM behaved identically in both
> >scenarios,
> >until we set it to 'enable_fencing=0' in the dlm.conf file.
> Do you have power or fabric fencing? Dlm requires former.
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Patrick Whitney
DevOps Engineer -- Tools

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