RDM share on two VM's?

[kpawelk]

Hi All,

I am struggling with RDM disk. I have two ESX 3.5 and two VM’s running on MS Windows 2003. My

question is can I connect the same Raw device to these two VM’s and if yes,

would I be able to use this drive on these VM’s the same time and share data?

Thanks,

Pawel

[Yattong · Accepted solution]

Hey Pawel,

Your limitation is the windows Guest OS.

What happens when you present the same LUN to 2 windows physical boxes?

(hint ~ There is a disk locking mechanism within NTFS)

If you are trying to create a microsoft cluster, have you read the manual?

www.vmware.com/pdf/vi3_35/esx_3/vi3_35_25_u1_mscs.pdf

~y

[kpawelk]

Hi Yattong,

That's make sense for me. When I connected the same Raw device to the VM's it dose not work as I want. I can see all space but I cannot see any changes made from another VM. Therefore it is like you said that this is limitation of OS.

I have not read this manual yet.

Thanks,

Pawel

[AntonVZhbankov]

To be exact it's FS level limitation. NTFS is not intended for true cluster use, i.e. simultaneous work with two hosts. You need cluster file system like OCFS which is specially designed for such situations - 1 disk + 2 hosts. Problem is NTFS just do not know that there are two hosts, it's for monopole access.

If you plan to use it just as common file storage, you need to setup 3rd VM, connect as RDM and share on network.

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http://blog.vadmin.ru

[kpawelk]

Is OCFS(2) working under Windows, I thought that this works only under the Linux?

Thanks,

PAwel

[AntonVZhbankov]

AFAIK there are no free cluster file systems for Windows. But there is Melio FS for example, from Sanbolic.

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http://blog.vadmin.ru

[kpawelk]

OK

thanks