Resource Pool Reservation and Limit Calculation
An administrator configures a resource pool with a reservation of 10 GHz and a limit of 20 GHz. The pool contains two VMs: VM1 has a reservation of 6 GHz and no limit, VM2 has no reservation and a limit of 8 GHz. The host has only 12 GHz available. During peak usage, both VMs demand more than their shares. Which statement is true?
Quick Answer
The correct answer is that VM1 gets at least 6 GHz, VM2 gets at most 8 GHz, but because the pool limit is 20 GHz and the host only has 12, VM2’s limit is effectively 6 GHz after VM1’s reservation. This outcome hinges on the resource pool reservation and limit calculation hierarchy: individual VM reservations are guaranteed first, then the remaining host capacity is distributed up to each VM’s limit, but the pool’s limit cannot exceed physical host resources. On the VMware Certified Professional Data Center Virtualization VCP-DCV exam, this scenario tests your understanding that a pool’s limit is a cap, not an allocation, and that host capacity can override it—a common trap is assuming the pool’s 20 GHz limit is reachable when the host only provides 12 GHz. Remember: reservations are floors, limits are ceilings, and the host is the roof. For a quick memory tip, think “reservation first, limit last, host capacity rules the cast.”
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
VM1 gets at least 6 GHz, VM2 gets at most 8 GHz, but because the pool limit is 20 GHz and host only 12, VM2's limit is effectively 6 GHz after VM1's reservation
The resource pool has a reservation of 10 GHz and a limit of 20 GHz, but the host only has 12 GHz available. VM1 has a reservation of 6 GHz, so it is guaranteed at least 6 GHz. VM2 has a limit of 8 GHz, which means it cannot exceed 8 GHz. However, after allocating VM1's reservation, only 6 GHz remains on the host (12 - 6 = 6), which is less than VM2's limit of 8 GHz. Therefore, VM2 effectively gets at most 6 GHz. The pool's reservation of 10 GHz is satisfied because VM1 gets 6 GHz and VM2 gets 6 GHz (6+6=12 >=10). The pool's limit of 20 GHz is not relevant because the host capacity is the bottleneck. Option B is incorrect because the remaining 0 GHz (12 - 6 - 6 = 0) cannot be divided by share. Option C is incorrect because VM2 cannot get 8 GHz due to insufficient host capacity. Option D is incorrect because the pool's reservation does not guarantee additional resources beyond individual VM reservations; it only ensures the total allocated to the pool meets that level.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
VM1 gets at least 6 GHz, VM2 gets at most 8 GHz, but because the pool limit is 20 GHz and host only 12, VM2's limit is effectively 6 GHz after VM1's reservation
Why this is correct
VM1's reservation takes 6 GHz, leaving 6 GHz for VM2, which is within VM2's limit of 8 GHz, so VM2 gets 6 GHz.
- ✗
VM1 gets at least 6 GHz, VM2 gets at most 8 GHz, and the remaining 4 GHz is divided by share
Why it's wrong here
The remaining host capacity after VM1's reservation is only 6 GHz (12-6), not 4 GHz, so sharing doesn't apply.
- ✗
VM1 gets exactly 6 GHz, VM2 gets exactly 8 GHz, and the pool's reservation is ignored
Why it's wrong here
Host only has 12 GHz, so VM2 cannot get 8 GHz; it gets 6 GHz.
- ✗
VM1 gets at least 6 GHz, VM2 gets at least 2 GHz due to pool reservation, and both use remaining as share
Why it's wrong here
Pool reservation does not allocate additional resources; it only guarantees that sum of VM reservations is at least pool reservation.
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Same concept, more angles
1 more way this is tested on VCP-DCV
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. An administrator configures a resource pool with a CPU reservation and expandable reservation enabled. The root resource pool has 100% of cluster CPU resources. A VM inside the resource pool with no reservation requests CPU resources. What will happen when the VM tries to power on?
medium- A.The VM can power on but will be limited to the resource pool's shares.
- ✓ B.The VM can power on using resources from the resource pool or its parent due to expandable reservation.
- C.The VM cannot power on because the resource pool has a reservation set.
- D.The VM can power on using resources from the resource pool only if it has a reservation.
Why B: With expandable reservation enabled, the resource pool can borrow CPU resources from the parent resource pool (root) if needed. Since the VM has no reservation, it does not require any guaranteed CPU capacity; it can power on as long as there are any unreserved resources in the resource pool or parent. Option A is incorrect because shares only affect priority during contention, not the ability to power on. Option C is incorrect because the reservation on the resource pool does not prevent VMs without reservations from powering on; it only guarantees that a certain amount of resources is reserved for the pool. Option D is incorrect because the VM does not need a reservation to power on; it can use unreserved resources from the pool or borrowed from the parent.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This VCP-DCV practice question is part of Courseiva's free VMware certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the VCP-DCV exam.