An administrator decreases the CPU share value for two virtual machines in a DRS cluster from
1000 to 100 shares. The DRS cluster contains more resources than both virtual machines can
consume.
The characteristics of the virtual machines are listed below:
• The second virtual machine is a clone of the first virtual machine.
• Both virtual machines are identical in every way.
• Both virtual machines are not attached to the IP network.
• Both virtual machines are powered on.
What impact on the virtual machines’ performance will be observed?
A.
The virtual machines will have equal performance under all conditions.
B.
The performance of the virtual machines will reduce by a factor of ten once the share value is
adjusted.
C.
The virtual machines will have equal performance under normal conditions and reduced
performance when contention occurs.
D.
The original virtual machine will perform better than the clone when contention occurs.
Explanation:
what’s wrong with C? i think c is also correct
A is correct since both VMS have equal CPU shares. Hence the virtual machines will have equal performance under all conditions.
Why not C? eg: DRS moves then to separate hosts. Different levels of contention occur on both hosts. Performance impact will not be the same.
C is correct
What is meant with THE virtual machines? Is it the same as BOTH virtual machines?
I would go for C. because there is no talking about Reservations or Limits…
Only Shares are involved with contention.
Reservation means an absolute minimum (physical use on the Host!)
Limit means an absolute maximum (physical use on the Host!)
BE AWARE This also limits the physical use by a VM despite the virtual amounts!
For example: the virtual mem (defined on the VM) is 8GB and the Limit is 6GB
When Powered on a VM will never us more than 6GB, so swapping can/will occur
when the VM needs whole 8GB!
(The same goes with CPU GHz’s)
Shares becomes active when contention occurs (physical use on the Host!)
It is the space between Reservation AND Limit.
NOTE: Contention is a physical issue on the Host itself!
Always keep in mind the difference between pCPU v.s. vCPU and pMemory v.s. vMemory.
Reservation AND Limit are in MB or MHz (not GB or GHz, sorry for the typo)
http://pubs.vmware.com/vsphere-55/index.jsp#com.vmware.wssdk.apiref.doc/vim.ResourceAllocationInfo.html?resultof=%2522%2563%256f%256e%2574%2565%256e%2574%2569%256f%256e%2522%2520
C says that there will be reduced performance but not necessarily equally reduced. A fits the question better since all aspects of the VMs are equal, then all performance good or bad will be equal.
There is no possibility for contention so A.
“The DRS cluster contains more resources than both virtual machines can
consume.”
David’s answers clarifies why it is not ‘C’. ‘A’ is correct.
Answer is A because they will have equal performance when there is no contention, and equally reduced performance when there is contention. Equally reduced is still equal, i.e. “equal performance under all conditions”
A is correct
DRS cluster contains more resources than both virtual machines can consume, so will have equal performance when there is no contention, and equally reduced performance when there is contention.
http://pubs.vmware.com/vsphere-55/index.jsp#com.vmware.wssdk.apiref.doc/vim.SharesInfo.html
Evil VMware, they intentionally give you errors so you can’t pass their EVIL exam, I hate them vigirously
The DRS cluster contains more resources than both virtual machines can
consume.
There will never be contention, thus A