KLeach
Contributor
Contributor

Windows 2008R2 VMs sharing a mount point?

I want to know if anyone has found a way to take a host lun and have it mounted on TWO (or more) Windows VMs.

I am trying to have two windows VMs share the same physical storage for a data drive. 

Where one VM prepares the data and writes to the drive.. the othe VM will see the same exact mount point and be able to read the file he other VM wrote.

I know you can use NAS and other forms of storage but you end up moving around data that does not need to be moved and that take time etc..

I have done this very thing in the past with TRU64 a flavor of unix... I don't think the NTFS supports this natively, so I was wondering if VMWare supported the config anf if so what file system woudl you need in Windows 2008R2 to get it to work?  (NFS???)

Thanks for the help... great forumn!!

-Ken

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7 Replies
DCjay
Enthusiast
Enthusiast

Hello Ken,

You can attach a VMDK to morethan one VM. The problem is NTFS is not smart enough to understand multiple request from different source.

You will need an OS that supports multi-homing.

In windows, it may need to data corruption.

Jay

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KLeach
Contributor
Contributor

Thanks for the quick feedback..

You are right.. using a NTFS file system would lead to corruption..

It is actually the file system not the OS (I thought) that has to handle the possible simultaneous writes.  That is why I was looking to see if anyone has accomplished this in windows.. using VMWare and a different file system than NTFS

-Ken

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DCjay
Enthusiast
Enthusiast

Yes Ken,  you are right, it is a file system issue. I have had countless customers requestion this configuration.

I am almost certain that as for now, windows dont support any filesystem that can achieve you aim.

If by chance you find  solution, please let me know how this was done.

Jay

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KLeach
Contributor
Contributor

seems like StorNext File System will do the job... may be some timing issues with VMs.

I am looking at the cost and getting trials..

Looks like a possible 10% speed hit to get the benefits of not having to transfer files over the LAN

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DCjay
Enthusiast
Enthusiast

It will interesting if it works fine. I recommend running a test before deploying it in a produting enviorment.

Is it supported by microsoft?

Jay

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AureusStone
Expert
Expert

Why not just map a network drive?  One server is the file server, the other just maps a network drive.

You would still be using the LAN to read data from the file server, but you wouldn't need to replicate the data.

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KLeach
Contributor
Contributor

using file server introduces LAN speeds and requires a move of the data.

By sharing the same spindle from two VMs there is no move.. when the local disk is written to on one host it is already on the second host.. no replication.. 1 disk two servers..  using lans will transfer that data via LAN and not Fiber Channel.. very differnet response times..

When I am trying to "move" a 50GB file... I don't want to use the LAN at all..

Does anyone have experience with microsoft alternate file systems that may work?

-Ken

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