Server Virtualisation part 2

Question 1

Explain the following benefit of virtualisation: Scalability

Answer 1

Virtually unlimited access to hardware resource, i.e. being able to start up a large infrastructure in a short period of time.

Question 2

What are two disadvantages of Virtualisation?

Answer 2

Some apps are not suitable for virtualisation. E.g. Gaming, Mission Critical.

Virtualisation process adds overhead, which will make some apps run more slowly.
check diagram in notes

Question 3

What are LinuX Container(LXC)?

Answer 3

Lightweight virtual machines (VMs) which are realised using features provided by a modern Linux kernel (e.g. namespaces and cgroups) - VMs without the hypervisor.

• -an operating system-level virtualisation
• -multiple isolated Linux systems (containers) on a single control host
• -the virtual environment has its own process and network space

Question 4

LXC VS Hypervisor

Answer 4

check notes for diagram

Question 5

Explain the motivation to virtualise due to improving resource utilisation.

Answer 5

Improves resource utilisation:

• -average servers’ utilisation is in between 40%-70%
• -improve return on investment
• -achieved by adding more VMs onto physical servers

Question 6

Explain the motivation to virtualise due to load balancing.

Answer 6

Load balancing:

• -performance impairment when there is resource contention
• -live migration - moving a running virtual machine or application between different physical machines without disconnecting the client or application.
• check notes for diagrams*