Test Information Space

Journal of Tech, Testing and Trends

Instant Virma

Posted by cadsmith on September 27, 2009

“It prospered strangely, and did soon disperse
Through all the earth:
For they that taste it do rehearse
That virtue lies therein”

George Herbert, Peace, 1633.

In this case the wide-spread subject is virtualization. This makes a computer or storage system look like many to its users. Popularity is due to the costs and power saved by not having to load up on hardware, often to meet a temporary peak demand, and the agility in fielding appropriate infrastructure and applications. Sometimes it is as easy as drawing a capacity plan and having the hypervisor and virtual machine monitor assemble the hardware emulation software automatically on hosted servers, tuning each virtual machine (VM) instance’s portion of resources such as processor instruction cycles, memory or bandwidth for proper load balancing.

The techniques sprang from time-sharing, portable OSes, and redundant storage devices. Of course, hardware was also often developed using simulation and functionality implemented in firmware. Now the bare metal can host a layer which mimics popular processor, memory, I/O, and network switch architectures so that off-the-shelf applications can run anywhere, operating system optional, and migration is easier. This is offered for servers, desktops, phones and data centers. The approach spans cloud, grid, parallel and high-performance computing (HPC) systems. Vendors include VMWare, Microsoft, IBM, Intel, Oracle, Cisco and many others. There are open-source versions which lower cost further if vendor support is not necessary, e.g. Xen and KVM. Hardware may also have virtualization built in as a multiplier and for compatibility to a variety of interfaces, for instance.

System management is significant since integration issues are likely and software may require licensing. A virtual machine often has to reboot when a bug causes a crash, but the rest of the VMs run intact. Version changes introduce risk. Infrastructure patches cause side-effects to virtual apps. It is possible to mix various ratios of physical and virtual components. Performance may be adversely affected by additional virtualization layers. VM sprawl makes end-to-end administration more difficult. The visibility and testing tools need improvement. Standard quality measures can still be taken, such as use cases, architectural review, and measures of functionality, usability, security, scalability and performance. Benchmarking in VMs may have time drift.

Users, developers and administrators can expect to see this topic expand as more virtual appliances are developed. Here is an example introductory Glossary.

Also see bookmarks. Tags can be combined as subtopics, e.g. taxonomy or test. A sampling of additional literature on virtualization and grid computing is shown below.




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