Question

Virtualization software is being aggressively deployed to reduce the costs of managing today’s high performance servers. Companies like VMWare, Microsoft and IBM have all developed a range of virtualization products. The general concept, described in Chapter 5, is that a hypervisor layer can be introduced between the hardware and the operating syste, to allow multiple operating systems to share the same physical hardware. The hypervisor is then responsible for allocating CPU and memory resources, as well as handling services typically handled by the operating system (e.g., I/O)

Virtualization provides an abstract view of the underlying hardware to the hosted operating system and application software. This will require us to rethink how multi-core and multiprocessor systems will be designed in the future to support the sharing of CPUs and memories by a number of operating systems concurrently.

6.10.1 [30] Select two hypervisors on the market today, and compare and contrast how they virtualize and manage the underlying hardware (CPUs and memory)

6.10.2 [15] Discuss what changes may be necessary in future multi-core CPU platforms in order to better match the resource demands placed on these systems. For instance, can multithreading play an effective role in alleviating the competition for computing resources?

Short answer

6.10.1 – The hypervisors, VMware ESX and WMWare ESXi are compared and contrasted.

6.10.2 – Software reliability

Step-by-step solution

Hypervisors

A hypervisor, also known as a virtual machine monitor, is a process that creates and runs virtual machines (VMs). A hypervisor allows one host computer to support multiple guest VMs by virtually sharing its resources, like memory and processing. Generally, there are two types of hypervisors. Type 1 hypervisors, called “bare metal,” run directly on the host’s hardware. Type 2 hypervisors, called “hosted,” run as a software layer on an operating system, like other computer programs.

Comparison between VMware ESX and VMware ESXi

VMware ESX and VMware ESXi are hypervisors which install directly on top of the physical server and partition it into multiple virtual machines that can run simultaneously, sharing the physical resources of the underlying server.

Operational management and architecture are the two areas where the main difference between the two hypervisors lie. ESXi is made with the latest architecture from VMware while ESX is made with previous generation architectural firmware. ESXi is noted to be preinstalled on several x86 servers. Both hypervisors do not rely on the Operating System for resource management, but ESX depends on the Linux OS, called service console to execute scripts and to install third part agents which can be used to monitor hardware and backup management. The service console is removed from the ESXi which reduces its footprint. The function of the service console is replaced with the help of remote command line interfaces. It adheres to the management standards of the system.

Necessary changes in the future multi-core CPU platforms.

The following changes may be necessary in the future CPUs:

1. Software reliability
2. Advanced application performance.
3. Temperature control for the CPU and
4. Improvement on concurrency handling.

Multi-threading can play an effective role in alleviating the competition for computing resources because when a processor has multiple tasks to do single handedly, multi-threading can make the responsiveness faster. We can work on many processes parallely by using multi-threads. The background tasks can run easier and the performance and speed will be improved on the multi-core because of multi-threading.