NCA-5.15 · Question #40
An application owner had reported that an AHV-based critical application VM is performing very slowly. After initial diagnostics, it has been observed that the CPU utilization is significantly…
The correct answer is A. Increase number of vCPU in Prism Element C. Ensure CPU hot-add is supported by the Guest O. Adding CPU resources to a running (live) VM requires CPU hot-add support from both the hypervisor and the guest OS. AHV supports vCPU hot-add at the hypervisor level, but the guest OS must also be capable of recognizing and using newly added vCPUs without a reboot - Windows…
Question
An application owner had reported that an AHV-based critical application VM is performing very slowly. After initial diagnostics, it has been observed that the CPU utilization is significantly higher than normal. What two actions should the administrator take on this VM without shutting it down? (Choose two.)
Options
- AIncrease number of vCPU in Prism Element
- BConfigure additional cores in acli
- CEnsure CPU hot-add is supported by the Guest O
- DUse PrismElement to increase the number of cores
How the community answered
(37 responses)- A81% (30)
- B14% (5)
- D5% (2)
Explanation
Adding CPU resources to a running (live) VM requires CPU hot-add support from both the hypervisor and the guest OS. AHV supports vCPU hot-add at the hypervisor level, but the guest OS must also be capable of recognizing and using newly added vCPUs without a reboot - Windows Server 2012+ and modern Linux kernels support this, but not all OS versions do. Therefore, the administrator must first verify guest OS compatibility (C), then use Prism Element to increase the vCPU count (A). Increasing cores per vCPU (B via acli, D via Prism) requires a VM power-off in AHV - it is not a hot-add operation - so those options violate the 'without shutting it down' constraint.
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