VMWare & Microsoft Failover Cluster

zito2000
zito2000 used Ask the Experts™
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Hello,

I was wondering if someone had some knowledge on VMWare with Microsoft Failover Cluster Manager.
I need to understand the following:
I have my 2 VM's setup using RDM disks that are pointing to the same LUN on my SAN.  They are in an active/passive setup and they share an "E" drive in Windows.
My question is, when I look at the disks themselves, it shows that there are 2 separate VMDK files on each of the server.  But again, they are pointing to the same actual physical LUN.
Is this by design?  
I'm sure that is a very watered down explanation, so feel free to ask any questions you may have to help clear it up.

Thank you so much for your time.
Happy Friday.
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Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017

Commented:
Have you followed the cluster guide ?

https://docs.vmware.com/en/VMware-vSphere/6.5/vsphere-esxi-vcenter-server-651-setup-mscs.pdf

The VMDK are just pointer files for the RDM, and it's the same LUN presented to two VMs
zito2000Network Manager

Author

Commented:
Andrew, thank you for the input.  I am going to look at the link.
I'm sure that it was followed at some point, but I wasn't the one that built the environment, so I'm trying to learn it.
I thought about it being a pointer file as well, but I was thrown off as to why each unique VMDK was the size of the entire disk.

For instance:
Node1 VMDK: Server1_3.vmdk (650GB in size)
Node2 VMDK: Server2_3.vmdk (650GB in size)

So why would it be 1300GB in size total for a 650GB disk?  
Does that make sense?

Thanks again.
VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017
Commented:
Have a read of this link which describes why a VMDK (proxy file is required).

https://vmwareaddicted.blogspot.com/2017/05/raw-device-mapping-rdm-in-detail.html

So every VM which uses a RDM creates a pointer file (proxy mapping).

You have two VMs access a RDM, so there is a pointer file for each.
zito2000Network Manager

Author

Commented:
Thanks for your help, Andrew.  The article was helpful as well.

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