A vSphere administrator is configuring a fully automated DRS cluster and determines that DRS is
not balancing virtual machine workloads.
What condition could cause this behavior?
A.
vMotion is not properly configured on the hosts in the cluster.
B.
HA is not properly configured on the hosts in the cluster.
C.
The DRS threshold is configured on the most aggressive setting.
D.
Some of the virtual machines have been disabled from DRS.
Explanation:
A. Is not valid, because you will NOT be able to Enable DRS.
http://pubs.vmware.com/vsphere-55/index.jsp?topic=%2Fcom.vmware.vsphere.resmgmt.doc%2FGUID-CAF3CDC4-469F-4FA4-ACFD-24F5F36847EA.html
B. Is not valid, because it has NOTHING to do with load balancing!
HA kicks in when a ESX(i) Host stops working (Power Failure) or gets Isolated (Network Failure). HA will restart the involved VM’s on another ESX(i) Host in the Cluster.
C. Is not valid, Just the opposite. (Threshold set on most conservative(!) could be the answer)
http://pubs.vmware.com/vsphere-55/index.jsp#com.vmware.vsphere.resmgmt.doc/GUID-23A2BE80-BCE2-49D7-902E-F7B8FDD8F5F8.html
D. Disabling some virtual machine from DRS does not mean other VM’s would NOT be vMotioned by “Fully Automated DRS”, does it? But if EVC is Disabled for some VM’s…
http://pubs.vmware.com/vsphere-55/index.jsp#com.vmware.vsphere.resmgmt.doc/GUID-C21C0609-923B-46FB-920C-887F00DBCAB9.html
So my choice would be D.
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Agreed with this researching again. Seems you can have DRS without vmotion network for initial placement purposes. Valid setup apparently.
http://pubs.vmware.com/vsphere-51/index.jsp?topic=%2Fcom.vmware.vsphere.resmgmt.doc%2FGUID-56E9F25B-7CD7-4AB4-B4DD-5E8A0D8D06AC.html
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Since it is ‘fully automated DRS cluster'(thats the clue) you need vMotion to place/balance/migrate vms. without vMotion DRS just makes placement recomendations
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vMotion can be enabled but still misconfigured, an example of this would be a duplicate IP address on hosts. My answer would be A for sure.
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Correct answer are “A”.
If “D. Some of the virtual machines have been disabled from DRS.” then virtual machines whith ENABLED DRS must migrate.
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How can vMotion not be configured properly?
The only thing I can think of is the vmkernel ports with vmotion.
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DRS might be disabled on enough of the VM’s that DRS can’t migrate enough of the rest to balance the cluster. I think ‘D’ is the answer here.
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Agree w/ Brendon, “D” is within the possible causes and it’s truly the most suitable answer here.
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From “ESXi and vCenter Server 5.1 Documentation > vSphere Resource Management > Creating a DRS Cluster > DRS Cluster Requirements:
To enable the use of DRS migration recommendations, the hosts in your cluster must be part of a vMotion network. If the hosts are not in the vMotion network, DRS can still make initial placement recommendations”
So, the question don’t say that it’s a initial placement recommendation, so I think that “A” is the correct answer.
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I am going with A. Thanks for all the analysis everyone!
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answer for your dispute is: in order to have fully automated DRS cluster you have to create vMotion port group under Network settings in vSphere. Even if vMotion port exist in your vSwitch, it doesn’t mean it’s configured properly. You have to make sure it’s enabled and has proper port and IP address config as shown on the pic below:
http://pawellakomski.pl/blog/wp-content/uploads/2012/09/vmotion2.png
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