[Pacemaker] fencing best practices for virtual environments

[Alberto Menichetti]

Hi all,

I'm setting up a two-node pacemaker cluster (SLES-HA Extension) on 
vmware vsphere 5.
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).
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.

Are there some best practices or validated configurations for a deploy 
like this?

Thank you.
Alberto