Solved

UnderStanding why MSCS in Vmware Requires RDM's

Posted on 2014-03-18
10
419 Views
Last Modified: 2014-03-21
I understand you need to use a RDM in the following situations.

1) A Vm that requires an extremely large hard drive greater that 2TB
2) A VM that needs to use SAN tools
3) Running MSCS

But what technical reason does MSCS require an RDM.

I have search the internet and cannot find a answer so I am turning to toughs who are more knowledge than I.... :o)
0
Comment
Question by:compdigit44
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 3
  • 3
10 Comments
 
LVL 120

Assisted Solution

by:Andrew Hancock (VMware vExpert / EE MVE^2)
Andrew Hancock (VMware vExpert / EE MVE^2) earned 250 total points
ID: 39938507
It comes down to what Microsoft will Support if you should have issues when you contact the support department. They will only entertain you if using RDM or RAW.

Because its physical. Eg VM accesses a physical device as the LUN is passed through RAW.

Software iSCSI can also be used, it works...its up to organisations to access the Risk if you need to discuss with Msoft if you have issues.

SCSI reservations and locking have been issues in the past.
0
 
LVL 120
ID: 39938508
Also VMDKs can now be up to 62TB so no RDM requirement...if you want a super size disk.
.
0
 
LVL 20

Author Comment

by:compdigit44
ID: 39939344
Thanks for your response so there is not other technical reason why a RDM is required for MSCS except for certified support????

So when you map a LUN to a physical server it is a RAW mapping correct?

Has anyone tried to setup MSCS using VMDK?

There has to be a least one technical reason why MS still requires this besides from the support aspect..
0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 62

Accepted Solution

by:
gheist earned 250 total points
ID: 39940662
Yes, you can share VMDK as mscs quorum
VAAI accelerated SAN/NAS recommended, but no problem without one.
0
 
LVL 20

Author Comment

by:compdigit44
ID: 39941001
Interesting I wonder if times goes on if MS will change there stance on this.
0
 
LVL 62

Expert Comment

by:gheist
ID: 39941085
Microsoft support is pay-per-event anyway...

See this:
VMWare KB1037959
0
 
LVL 120
ID: 39941426
Correct when you map a LUN to VM it's RAW.

Virtual bus sharing works for VMDK.

Again access the risk we no very few clients that log support calls with Microsoft.
0
 
LVL 20

Author Comment

by:compdigit44
ID: 39942213
I read the VMware KB you posted earlier. At the end of the document it states the following.

"VMware vSphere 5.5 provides complete support for 2012 failover clustering"

Does this mean VMware / MS support a Failover cluster running on a non-RDM?
0
 
LVL 120
ID: 39944383
In 5.5 there are new enhancements for Failover Clustering in 2012 in which RDM do not need to be used eg iSCSI

See this kb
http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&docType=kc&docTypeID=DT_KB_1_1&externalId=2052238
0
 
LVL 62

Expert Comment

by:gheist
ID: 39945986
Microsoft supports hyper-v virtualisation, for other stuff you contact virtualisation vendor.
0

Featured Post

Free learning courses: Active Directory Deep Dive

Get a firm grasp on your IT environment when you learn Active Directory best practices with Veeam! Watch all, or choose any amount, of this three-part webinar series to improve your skills. From the basics to virtualization and backup, we got you covered.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

HOW TO: Upload an ISO image to a VMware datastore for use with VMware vSphere Hypervisor 6.5 (ESXi 6.5) using the vSphere Host Client, and checking its MD5 checksum signature is correct.  It's a good idea to compare checksums, because many installat…
In this article, I will show you HOW TO: Perform a Physical to Virtual (P2V) Conversion the easy way from a computer backup (image).
Teach the user how to edit .vmx files to add advanced configuration options Open vSphere Web Client: Edit Settings for a VM: Choose VM Options -> Advanced: Add Configuration Parameters:
Teach the user how to configure vSphere clusters to support the VMware FT feature Open vSphere Web Client: Verify vSphere HA is enabled: Verify netowrking for vMotion and FT Logging is in place or create it: Turn On FT for a virtual machine: Verify …

738 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question