Assuming that ballooning is possible, under which three circumstances might the VMkernel use a swap file for a running virtual machine?
A.
The Mem CtlMaxPercent value is between 10 and 25 percent
B.
Memory cannot be reclaimed quickly enough
C.
The virtual machine is starting up
D.
VMware Tools is not installed
E.
50 percent of the configured memory has already been balooned
Explanation:
C: Wrong: When the machine is starting up the Ballooning driver hasn’t loaded yet.
D: Wrong: When VMware tools is not installed Ballooning isn’t possible
The question asks “under which three circumstances might the VMkernel use a swap file for a running virtual machine?”
Because by default a VM swap file is created when a virtual machine starts, I think that the answer
C-The virtual machine is starting up
Is correct. This holds true even if ballooning is possible.
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Correct answers are B, C, D as per VMware’s balloon vs. swap criteria
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A,B,E are correct.. but the question is poorly worded though.. It says “ballooning is possible”, and C and D are two scenario that won’t have ballooning capability
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Balloon Drive only is possible when vmtools is running.
I belvieve: ABE
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Not sure about this one … Assuming that ballooning is posible doesn’t that mean that there is available memory ? So is this case D should be a good anwser ? also C ?
cheers,
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Also is vpshere 4 the Mem.CTlMaxpercent is set to 65%
http://pubs.vmware.com/vsphere-4-esx-vcenter/index.jsp?topic=/com.vmware.vsphere.resourcemanagement.doc_41/advanced_attributes/r_advanced_memory_attributes.html
And also even if this value is between 10 and 25% how can we bu sure that this will cause to swap instead of balloning ?
Hopefully this is not a real VCP question …
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The answer is B,C,D for sure.
Its not (A) because ballooning will start between the 10-15 value and SWAP will be used if it keeps dropping to 2 percent.
B Because if the value starts to drop to 3 or 2 percent then SWAP will happen. Which is not being recalled fast enough.
C Because during startup the drivers will not be loaded
D Becuase you need VMtools installed to work.
Its not (E) becuase simply its not a true statement
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IMHO: BCD and sentence “Assuming that ballooning is possible” means only that it is not disabled, I think.
http://pubs.vmware.com/vsphere-51/index.jsp?topic=%2Fcom.vmware.vsphere.resmgmt.doc%2FGUID-B55F4F6B-44E6-46DE-B8FF-75950020A181.html
Using Swap Files
You can specify the location of your swap file, reserve swap space when memory is overcommitted, and delete a swap file.
ESXi hosts use swapping to forcibly reclaim memory from a virtual machine when the vmmemctl driver is not available or is not responsive.
■ It was never installed.
■ It is explicitly disabled.
■ It is not running (for example, while the guest operating system is booting).
■ It is temporarily unable to reclaim memory quickly enough to satisfy current system demands.
■ It is functioning properly, but maximum balloon size is reached.
Standard demand-paging techniques swap pages back in when the virtual machine needs them.
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