How to connect VM to the storage?

[kpawelk]

Hi All,

I have not tried connect storage to the Virtual Machine(Windows 2003) yet. I have four virtual machines based on ESX 3.5 servers (two). I have the SAN storage connected to the ESX and I store VM on this SAN.

My question is what is the best way to connect storage to these VM's. Do I need create a new storage for these VM's or can I use existed SAN(vmfs)?

Many thanks for any suggestion,

Pawel

[depping]

I'm not really sure that I understand your question correctly. But the easiest thing to do is just give the VM's that need additional storage an extra Virtual Hardisk. I would try to keep the VMFS between 300 and 500 GB max, and if you need more diskspace just create another VMFS.

Duncan

Blogging: http://www.yellow-bricks.com

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[AntonVZhbankov]

It all depends on your real needs. You can create new virtual disks on existing vmfs datastore, you can attach LUN from SAN to virtual machine as Raw Device Mapping disk.

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[kpawelk]

Hi Depping

Yes I can do this, but what I need to archive is to have a VM's and connect them to additional storage.

basically I have Windows 2003 with SQL and I do not want to store data on the same VM I want to store this data on separate storage system.

any idea?

[kpawelk]

Hi Anton V Zhbankov,

I think the Raw Device Mapping is what I want, but my question is if I would be able to format this disk as a NTFS?

Thanks,

Pawel

[Yattong]

Hey,

Thats exactly what a Raw Device Mapping is there for; so that you can format the LUN with the relevant file system to the Guest OS.

You will not be able to add a Raw device Mapping if the the LUN has been formatted with VMFS.

You would present the LUN to the ESX server and scan your hba. Then go to the vm and add the RDM.

~y

[kpawelk]

Thanks Yattong,

You will not be able to add a Raw device Mapping if the the LUN has been formatted with VMFS.

So do I need to use different LUN to use as a RDM?

Is it any tools to manage RDM?

Thanks,

Pawel

[AntonVZhbankov]

RDM disk consists of vmdk file with configuration (less than 1 kb) describing what LUN and what mode to use and the LUN itself.

VM will see it just as another SCSI disk. You can format it in NTFS, ext3 or any filesystem you like. Your VM has full control on LUN data.

You can VMotion VM, and RDM disk works perfectly, but ALL your hosts must have access to this LUN.

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[AntonVZhbankov · Accepted solution]

ESX don't care about LUN filesystem. It can be formatted even with VMFS. LUN must not be included to any datastore.

Yes, RDM disk is always another LUN.

For ex. you have 21TB and 4250GB LUNs. You can make 2TB VMFS datastore with big LUNs, while 4 smaller LUNs to be used as RDM disks for VMs. But if you add 250GB as an extent to VMFS datastore there's no way back. You'll have only 3 LUNs available for RDM. As for now you can't disconnect LUN from VMFS datastore without datastore destruction.

VI Client is enough to manage datastores and RDM disks.

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[kpawelk]

Many Thanks to Everyone,

Now on my W2K3 VM's can see RDM drive, but my question is if there is some option to share the same RDM drive on two VM's?

Thanks,

Pawel

[AntonVZhbankov]

From administration guide: "Use an RDM with virtual machine clusters that need to access the same raw LUN for failover scenarios. The setup is similar to that of a virtual machine cluster that accesses the same virtual disk file, but an RDM replaces the virtual disk file."

Yes, you can share this LUN between virtual machines, and even between virtual and physical machine (in Physical Compatibility Mode).

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