VMware & EMC: "sharing" a LUN between physical and virtual host

Hi,

Is it possible to allow a physical host to access a RDM (Raw Device Mapping) LUN?

We want to share a LUN between a virtual host and a physical host. I mean, both running servers must be able to access this same LUN simultaneously.
We had to declare this LUN as a RDM, according to some VMware's PDF documentation ; to make it accessible from a virtual host.

Right now, the LUN is OK from our virtual host and is seen from the physical host as an unknown disk.

Hosts are both running W2k3 and we're use ESXi 4.

Any idea?

Regards,

Etienne
lynxiumAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

vmwarun - ArunCommented:
Are you trying to do a N+1 Microsoft Clustering ?
0
Paul SolovyovskySenior IT AdvisorCommented:
Yes.  You would set up a RDM in physical mode since it is basically taking a NTFS, quorum, etc.. volume and using as an additional volume on the VM.

Create a LUN and map using MS clustering and do the same with the VM and a RDP in physical mode.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Paul SolovyovskySenior IT AdvisorCommented:
Just make sure to zone them correctly on the SAN so that both nodes have access to it.
0
The Ultimate Tool Kit for Technolgy Solution Provi

Broken down into practical pointers and step-by-step instructions, the IT Service Excellence Tool Kit delivers expert advice for technology solution providers. Get your free copy for valuable how-to assets including sample agreements, checklists, flowcharts, and more!

jakethecatukCommented:
RDM is the VMWare recommended route if you are using Microsoft clustering on a physical and virtual machine.

This guide is for ESX3, but will still be valid.
http://www.vmware.com/pdf/vi3_301_201_mscs.pdf
0
lynxiumAuthor Commented:
Thanks for your  quick responses
No it's not properly for a Cluster , basically we want to access these luns to backup data, and to share data between various hosts for our internal application.
0
jakethecatukCommented:
I wouldn't share LUNS betwen hosts unless you are using some cluster aware software as you will be asking for a whole heap of trouble.

If you want to share data between various hosts then you will need to attach the LUN to one server and put shares on the directories.
0
Paul SolovyovskySenior IT AdvisorCommented:
You can't do that as jake noted and if you do it you will have corrupt data as it will resignature the LUNs and you may lose your data.

A better solution is a NAS of a File Server with replication such as DFS
0
vmwarun - ArunCommented:
Unless you are trying to do MS clustering, never try to share LUNs since it would cause Data Corruption.
0
securitythreatCommented:
I hate to BUZZ in like this, but why would you want to cluster a VM?
0
jakethecatukCommented:
[securitythreat quote]I hate to BUZZ in like this, but why would you want to cluster a VM?[/quote]

He's not clustering :)
[lynxium quote]Thanks for your  quick responses
No it's not properly for a Cluster , basically we want to access these luns to backup data, and to share data between various hosts for our internal application.[/end quote]

Also, there are situations where people want to have a clustered environment where one node is on a physical server and the other node is on a VM server.
0
lynxiumAuthor Commented:
We have to make choices , and search again ...
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Storage

From novice to tech pro — start learning today.