[Pacemaker] fencing best practices for virtual environments

[Alberto Menichetti]

On 09/10/2012 12:15 PM, Lars Marowsky-Bree wrote:
> On 2012-09-10T10:45:30, Alberto Menichetti<albmenichetti at tai.it>  wrote:
>
>> thank you for the quick response.
>> Maybe SPOF is not the best definition, but when the vcenter is
>> unavailable the safety of my data is not guaranteed.
> The safety remains guaranteed; the availability of your service wouldn't
> be ;-)
>

Sorry, maybe I'm missing something, but suppose this scenario (also 
remember that, being a 2-node cluster, I had to set 
no-quorum-policy="ignore"):
1. the virtual center is unavailable
2. an event occurs that partition the cluster
3. at this point, both the nodes could try to start a filesystem 
resource, thus compromising the data safety.

>>>> The fecing device I'd like to use is sdb.
>>> If you have a working SBD setup, you do not need the external/vcenter
>>> plugin any more.
>> What about using 2 different fencing mechanisms?
> But why? It doesn't provide any benefit.
>
>> Do you think it could introduce some problems in the cluster or is
>> it a suggested/supported solution?
>> I'd like to use external/vcenter as first choice and rely on sdb
>> only if the first stonith mechanism fails (for example, because of
>> the vcenter unavailability).
> Why?
>
>
> Regards,
>      Lars
>


-- 
TAI S.r.l.

Alberto Menichetti
Area Mercato - Ingegneria dei Sistemi
System Engineer

50141 Firenze - Via Pazzagli, 2
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