Did you already see KB1016106 ?
In there it is explained how the shared LUNs for an MSCS cluster should have the perenially reserved flag set. Did you do that on each ESXi where one of the MSCS nodes might run ?
You can, as explained in the KB, easily do that with the Get-EsxCli cmdlet.
Proxy 502 error ?
The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /selfservice/microsites/search.do<http://kb.vmware.com/selfservice/microsites/search.do>.
Reason: Error reading from remote server
This works fine, but quite manual. I have about many MS clustered VM's with 20 RDM disks.
I am looking for a powercli script that will check for physical RDM's on a host, then set them to perenially true
Thanks in advance