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DanS72
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VMotion IS allowed to new host??

Hi

Usually people post because something isn't working - but I would like to know why something IS working, which I thought should not...!

I have just added new ESXi 5 hosts to my vCenter inventory with Intel X5675 CPUs (Core i7 32 nm).  They are not added to a cluster - just in at the top level.  Eventually they will take over from the existing cluster, which is made up of 3 ESX 4.0 servers, using an EVC mode of Core 2 (With E5440 & 5160 CPUs)

Now, I did not expect it to work, but I gave it a shot anyway, and it allowed me to VMotion from the old EVC cluster (in Core 2 mode) to the new host - and back again...

Should this work?  Does it mean the VMs are still using the Core 2 mode on the new hosts - even though they are not in an EVC cluster?  Or are we now able to migrate machines across generations of processors?

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Rubeck
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I'll say that this is due to the CPU feature set provided by your EVC baseline is fully supported on your target host outside the cluster...

If you power off the VM and power it on again on your new host, thereby exposing the new CPU features to the VM, the VM will fail trying to migrate back into the EVC cluster..

/Rubeck

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kiranchavan30
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migration will happen only if hosts/clusters are in same datacenter? However, to ans your Q, If VM is powered on/off pre and post migration then vice-versa VM migration will work. I would like to suggest you to try to migrate any live VM without powered on-off process..

KC

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DanS72
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Yes - everything is in the same datacenter.  The VM was powered on already - I did not power it off at all, and it live migrated successfully...

DanS

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Rubeck
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I'll say that this is due to the CPU feature set provided by your EVC baseline is fully supported on your target host outside the cluster...

If you power off the VM and power it on again on your new host, thereby exposing the new CPU features to the VM, the VM will fail trying to migrate back into the EVC cluster..

/Rubeck

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DanS72
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Yes - you are right!  It did indeed fail validation after being powered off and on.  I am still suprised it was allowed to move, but it will certainly make things easier - and perhaps for others too - when moving to new hosts.

DanS

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Rubeck
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Your EVC cluster provides CPU feature A, B and C, which is dictated by the EVC baseline....  Your new host outside the cluster provides A,B,C and D...

So no problem moving it from the EVC enabled cluster to the new host as the running VM only sees and relies on A,B and C being available on the target. Powering it on outside the cluster, makes the VM rely on CPU feature A, B,C and D being available on the target which is not the case when trying to move it back in.. 

/Rubeck

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