CompTIA DataSys+ (DS0-001)Database DeploymentHard
A database administrator is evaluating a database server for a new application that will experience predictable, high sustained read and write throughput, but with occasional spikes in demand. The current plan is to use a virtual machine (VM) with dedicated resources. Which of the following virtualization features is MOST important to ensure consistent performance during peak loads?
- AResource reservation (CPU, RAM, I/O)
- BSnapshot and rollback functionality
- CDynamic memory ballooning
- DLive migration capability
Show answer & explanationAnswer & explanation
Correct answer: A. Resource reservation (CPU, RAM, I/O)
Resource reservation (for CPU, RAM, and I/O) guarantees that the VM will always have access to a minimum amount of physical resources, preventing resource contention with other VMs on the same host. This is crucial for ensuring consistent, predictable high performance and avoiding 'noisy neighbor' issues during peak loads for a database.
Why the other options are wrong
- B. Snapshot and rollback are useful for disaster recovery or testing, but they do not directly ensure consistent performance under load.
- C. Dynamic memory ballooning allows the hypervisor to reclaim unused memory from a VM, which can lead to performance degradation if the database suddenly needs more memory during a spike.
- D. Live migration allows moving a running VM, which is good for maintenance but doesn't guarantee consistent performance during peak loads.
Virtual Machine Resource Reservation
Resource reservation in virtualization guarantees a specific amount of CPU, memory, and/or I/O resources to a virtual machine, preventing resource contention.
- Ensures consistent performance for critical applications like databases.
- Prevents 'noisy neighbor' syndrome where other VMs consume shared resources.
- Sets a minimum threshold for resource allocation that the hypervisor must enforce.
- Crucial for production databases where predictable performance is paramount.
Memory trick: Reservations 'R'eally 'R'eserve 'R'esources.