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We have 4 ESXi 5.0 hosts in a VMWare cluster on shared storage (NFS) with DRS and HA on.

We want to perform a memory upgrade on one of the hosts. We put that host in maintenance mode but DRS did not automatically live migrate the VMs.

I'm thinking it has something to do with our settings:

enter image description here

I'm admittedly not that familiar with with VMWare's DRS. Can someone offer us some guidance on this?

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We may need more information. Did any VMs move? – ewwhite Dec 26 '13 at 16:26
None of the VMs moved. – Belmin Fernandez Dec 26 '13 at 16:29
up vote 6 down vote accepted

This should work, but there's more about your environment that we'd need to know. Your issue is most likely tied to the Admission Control settings for your 4-host cluster. The specifics of how to configure Admission Control properly is outside the scope of this question, though.

Can you try disabling HA Admission control and attempting the Maintenance Mode on the host again?

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That did it. I think I kind of understand why. Basically: If we go down to 3 hosts, we won't have enough for a 1 host failure. Is that it in a nutshell? – Belmin Fernandez Dec 26 '13 at 16:40
On the surface, yes... but the Admission Control doesn't mean what people think it means. It's pretty useless for the scale of your cluster unless you're using reservation pool or reservations at the VM-level. – ewwhite Dec 26 '13 at 16:50

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