[Pacemaker] fencing best practices for virtual environments

[Alberto Menichetti]

On 09/09/2012 09:53 PM, Lars Marowsky-Bree wrote:
> On 2012-09-09T13:30:36, Alberto Menichetti<albmenichetti at tai.it>  wrote:
>
>> I've successfully configured and tested the stonith plugin
>> "external/vcenter"; but this plugin introduces a single point of
>> failure in my cluster infrastructure because it depends on the
>> availability of the virtual center (which is, in the customer
>> environment, a virtual machine).
> It's not exactly a single point of failure, since you need two failures
> for this to matter - the first failure being the one that causes the
> fence, and a second one for the vcenter instance to be down at that
> time.
>

Hi Lars,

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.

>> I was thinking to introduce an additional fencing device, to be used
>> when the virtual center is unavailable; is this a suggested
>> deployment?
>> 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?
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).

>
> Regards,
>      Lars
>
Take care,
Alberto

-- 
TAI S.r.l.

Alberto Menichetti
Area Mercato - Ingegneria dei Sistemi
System Engineer

50141 Firenze - Via Pazzagli, 2
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e-mail: alb.menichetti at tai.it
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