Raw Device Mapping / Basic question

[AWahlert]

Hi List,

i'm totaly new to rdm, so i have a basic question. I have a LUN Snapshot (Dell Clariion CX3-20) from an NTFS Lun (1 TB, many Windows File like doc, pdf and so on).

Can i mount this snapshot in an VM? Can i use RDM for doing this?

if so, can someone explain this a little bit in detail?

kind regards

Andreas

[Chamon]

For it to be an RDM it needs to be an unformatted LUN. So this wont work as far as I know. You could create an RDM drive on your VM and copy the data into it.

[AndreTheGiant]

A RDM disk is just a SAN disk "directly" attached to a VM (hypervisor act a proxy to the resource).

There are 2 mode to use RDM: virtual and physical. In virtual mode you can do VMware snapshot of the VM, in physical (needed for cluster) no.

On the storage, you must mask the RDM LUN to all of your cluster's ESX.

Andre

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[Chamon]

But one cannot attach an existing SAN snapshot to a VM through RDM. So

the answer is no you can not.

On May 27, 2009, at 11:58 PM, AndreTheGiant <communities-emailer@vmware.com

[AndreTheGiant · Accepted solution]

The question was:

I have a LUN Snapshot (Dell Clariion CX3-20) from an NTFS Lun (1 TB, many Windows File like doc, pdf and so on).

If is a snapshot of a physical system the answer is yes (CX snap are the same as LUN).

If is a snapshot of a VM with a RDM, the answer is "maybe" (you need to play with LVM advanced options).

Andre

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[AWahlert]

Many thanks for the replys.

it's a physical Snapshot directliy on the SAN. i'm going to try this. My ESX Servers can see the lun.

OK, and now RTFM

Again, many thanks

Andreas

[AndreTheGiant]

You're welcome.

Andre

[AWahlert]

Yehaa,

it's done!

kind regrads

Andreas