- LPU MCA Semester 1
- CAP470
- Unit 3
CAP470 · Unit 3: Cloud virtualization
Virtualization: components, characteristics, types, advantages and disadvantages
10 practice questions · in the MTE and ETE syllabus
Key points
- Virtualization abstracts hardware into virtual resources
- Consolidation raises utilisation and cuts cost
- Overhead and host failure are the main drawbacks
- Virtualization enables cloud but is not the same thing
Virtualization creates a virtual version of a resource, such as a server, storage device or network, by adding an abstraction layer over physical hardware. Core components are the host (physical machine), the hypervisor that manages virtual resources, and the guests (virtual machines).
Types: server, storage, network, desktop and application virtualization.
Advantages: server consolidation (fewer machines, lower power and space cost), higher utilisation, isolation between workloads, faster provisioning, easier backup and disaster recovery, and flexibility in running different operating systems.
Disadvantages: performance overhead, a single point of failure if the host or hypervisor fails, resource contention when over-committed, licensing and management complexity.
Virtualization is an enabling technology for cloud, while cloud adds self-service, elasticity and metering on top.
Exam trap: virtualization and cloud computing are not the same thing.
Try two questions
A company finds that a virtualized host slows down because the virtual machines together ask for more memory than exists. What is this problem called?
- Hypervisor abstraction layer
- Storage tiering
- Network segmentation
- Resource over-commitment
Show the answer
D. Allocating more virtual resources than the host really has can slow all guests when demand peaks.
Why not A: Abstraction is the normal job of the hypervisor.
Why not B: Tiering moves data between storage classes.
Why not C: Segmentation splits networks and does not cause memory shortage.
A company replaces 20 lightly used physical servers with 4 hosts that run many virtual machines. Which advantage is shown?
- Lower hardware, power and space cost
- Complete removal of every operating system licence
- Faster speed than physical hardware for every task
- A guarantee against any hypervisor failure at all
Show the answer
A. Fewer, better-used servers need less hardware, electricity and floor space.
Why not B: Virtual machines usually still need licences.
Why not C: Virtualization often adds a small overhead.
Why not D: A hypervisor failure can still affect its guest machines.