timbo475
Contributor
Contributor

ESXi 4.1 Clone (and RDM mapping to vmdk files)

Hi,

I'm wanting to clone a VM that has a number of RDM disks attached. I've been browsing the datastore and the RDM disks appears as vmdk files, with their size listed. The actual VM vmdk file is called Server1.vmdk andf the RDM files are Server1_1.vmdk, etc.

A couple of questions:

- from reading around it seems the vmdk files are just metadata files that represent the RDM disks (I know the actual size state isn't contained in the vmfs datastore because there is not enough room for these disks in there). How am I supposed to tell which vmdk files are actually (taking up real space reported in 'size' column) and which are just metadata files (which aren't taking up the real space reported)? In this instance it's obvious to me but is there any way to identify between vmdk files that are taking up the real space and which aren't?

- If I clone this machine what happens to the RDM vmdk metadata files (how much space will I need to accommodate them)?

Cheers,

Tim

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DSTAVERT
Immortal
Immortal

Here is the KB article http://kb.vmware.com/kb/1005241

-- David -- VMware Communities Moderator
timbo475
Contributor
Contributor

Thanks - so does cloning follow this behaviour exactly? This kb seems to suggest that in a cold migration the RDM disks are converted to virtual disks. This is exactly what I'm trying to avoid. If this is the case then the only way to stop the RDMs being converted is to remove them from the VM prior to cloning. I have no intention of running the original machine and the clone concurrently (the clone is just to make sure I've got a copy of the VM to fall back to). I may use snapshots instead.

Cheers,

Tim

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DSTAVERT
Immortal
Immortal

Just noticed Clone

You can only clone virtual compatibility mode RDMs. The RDM will become a VMDK so you will need as much space as the original LUN. You can convert from physical RDM to virtual RDM http://kb.vmware.com/kb/1006599

-- David -- VMware Communities Moderator
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DSTAVERT
Immortal
Immortal

You can use VMware Standalone Converter to clone the just disks you want to convert. http://vmware.com/go/converter

-- David -- VMware Communities Moderator
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DSTAVERT
Immortal
Immortal


sure I've got a copy of the VM to fall back to). I may use snapshots instead.

SAN snapshots not VMware snapshots correct.

-- David -- VMware Communities Moderator
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DSTAVERT
Immortal
Immortal

This is a great way to clone one or more VMs. http://communities.vmware.com/docs/DOC-9843

Can clone just the boot disk, can be scheduled and pick and choose VMs.

-- David -- VMware Communities Moderator
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timbo475
Contributor
Contributor

Thanks.

I possibly should have put in a bit more info about what I was trying to do.

Basically,   I'm updating an application (Veritas Storage Foundation 5.1) and want   to make sure this update doesn't cause major problems on the VM as I've   been told by colleauges that previous attempts to apply the update has   caused problems.

I'm not too worried about the RDMs  themselves as it's  only C:\ that will be affected so I might just use  VMware snapshot to  give me the abilitity to return to the VM state  prior to the update. I  was hoping to use cloning as an ultimate  fall-back but hopefully  shouldn't really need it and it seems that  although it can be done it's a  fair bit more complicated to use it the  way I wanted (I was hopiing the clone would retain all the mappings to  the RDMs so I didn't have to faff about with the RDMs at all).

Cheers,

Tim

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AndreTheGiant
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Immortal

If your concern is about the C: disk, then you can poweroff the VM and take a copy of the relative vmdk (also with datastore browser).

To restore it, you have only to power-off the VM and replace the vmdk.

Andre

Andre | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
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