Thin migrate VM's from 3.5 to 4.1?

[hutchingsp]

As subject really, we currently have a cluster running 3.5 U4 and in a couple of months we're replacing the lot with a new cluster running 4.1.

Is there a way (offline I guess) to migrate the VM's across but to make the disks thin?

Lots of our VM's are created from the same 20gb VMDK template and obviously that's about 10-12gb wasted per VM on most of them.

Thanks a lot.

[Troy_Clavell · Accepted solution]

you can power down the guest and then migrate (choose change both host and datastore, or change datastore)... When you get to disk format, choose Thin Provisioned format

[hutchingsp]

Oh wow I really didn't expect it to be that simple (not got the new kit yet to be able to do any kind of testing of actually migrating).

So how does it deal with, say, a Windows VM that was filled with data, but most of the data was then deleted? Is it clever enough to work out that it only has to migrate (say) 5gb, or would it migrate all 19gb or whatever the "most full" was that it got?

Thanks

[jamesbowling]

I would build out your new vCenter server and then remove the hosts from the 2.5 VirtualCenter and connect them to the 4.1 vCenter. You can manage the 3.5 hosts in vCenter 4.X. At this point you could then do Storage vMotion and change the VMDKs to Thin Provisioned. Remember that you will need to make sure that you upgrade VMware Tools on these VMs when you move them to a 4.1 host. Just migrate the VM to a 4.1 host then power it on, upgrade VMware Tools. After the upgrade of the tools is complete, power the VM off and upgrade the virtual hardware to v7. This will put you in a spot to make the changes and bring everything up to speed as well.

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[Troy_Clavell]

you can use sdelete if there is to recover the space, if needed. Below is a good how to

http://www.virtualizationteam.com/virtualization-vmware/vsphere-virtualization-vmware/vmware-esx-4-r...

[hutchingsp]

Thanks James, I hadn't dug too deep into exactly the best way to migrate since we're small enough that most VM's could be done offline, though I did figure I'd be making use of the "30 day trial" licenses with the new 4.1 stuff whether I joined them to the 2.5 vCenter or whether I joined the "old" hosts to the 4.1 vCenter.

I think being able to thinly migrate, combined with thin provisioning on the new SAN (HP P4000) will save us a shedload of disk space.

[jamesbowling]

Unfortunately, you wouldn't be able to manage the 4.1 hosts in VirtualCenter 2.5. They can only be managed from vCenter 4.1. So you would have to connect your 3.5 hosts to the 4.1 vCenter installation.

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[hutchingsp]

Thanks Troy (and James), I seem to be unable to award more "Helpful" marks but cheers!

We'll only have Standard licenses, however I guess that guide still counts if you do the storage move offline so it could well come in useful.

James, makes sense on the vCenter stuff, I should have thought of that tbh as once I read it it's so obvious.

[Troy_Clavell]

also, if I missed the part of the question when you were going from one vCenter to another, my solution would not work. You could use VMware Converter.

[jamesbowling]

Glad we could point you in the right direction!

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[hutchingsp]

OK just to be clear we're not at cross-purposes, bring up a new 4.1 vCenter box, join the 3.5 hosts to it as well as the new hosts, then do a migration (live or offline) and just choose thin when prompted?

[jamesbowling]

Sounds good to me.

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[Troy_Clavell]

yes, if you choose to disconnect and add the hosts into the new environment, then go from thick to thin, my solution will work.