I have used a number of different types of virtualisation technologies over the years in IT from local desktop virtualisation to VMWare ESX server implementations.
As a developer i used alot of local desktop virtualisation technologies to test various platforms to run particular software which we built. The main driving benefit of using this technology was that we didn't have to have different hardware for different Operating Systems. All the operating systems could be run locally on the same machine so that we could ensure that our custom software could be deployed and run successfully without any issues.
Because of this technology it not only saves huge amounts of capital, because of not having to buy all the physical server. But huge amounts of time, as virtual desktop instances could easily be created while still working on the local machine.
Some of the virtualisation desktop software i have used is virtual desktop by microsoft, parallels, and virtual box
Saturday, September 11, 2010
Friday, September 10, 2010
Disadvantages with Server Virtualisation
With all things technology there are advantages and disadvantages for all emerging technologies. Earlier i spoke about advantages of implementation of virtualisation, and how cost savings and server consolidation could be achieved with server virtualisation. Now im going to look at some of the disadvantages associated with virtualisation.
1. Magnified physical failures
Imagine you had 10 very important servers running on the one physical host and its internals (i.e. RAID controller fails) and wipes all the important information for all these machines.
2. Degraded Performance
Because more than one machine is running on the same physical host, performance can drop if all virtual machines need the resources at the same time. Leading to slower response times.
3. Increased Complexity
Virtualisation adds a new layer of complexity to the physical host running the machine, which in-turn can add considerable time and effort to work out the root cause of a problem if the issue is within the virtualisation layer.
4. Virtual Machine Spawl
Even though virtual server management can get quite complex, and installing a new machine can be quick. The problem might arise is that if the number of servers grows faster than the number of administrators who are supposed to manage them.
These are just a few of the disadvantages of virtualisation i have found on the internet related to virtualisation.
1. Magnified physical failures
Imagine you had 10 very important servers running on the one physical host and its internals (i.e. RAID controller fails) and wipes all the important information for all these machines.
2. Degraded Performance
Because more than one machine is running on the same physical host, performance can drop if all virtual machines need the resources at the same time. Leading to slower response times.
3. Increased Complexity
Virtualisation adds a new layer of complexity to the physical host running the machine, which in-turn can add considerable time and effort to work out the root cause of a problem if the issue is within the virtualisation layer.
4. Virtual Machine Spawl
Even though virtual server management can get quite complex, and installing a new machine can be quick. The problem might arise is that if the number of servers grows faster than the number of administrators who are supposed to manage them.
These are just a few of the disadvantages of virtualisation i have found on the internet related to virtualisation.
Monday, September 6, 2010
Benefits Virtualisation
Virtualisation, Cloud Computing, Green IT, have all been touted as the next big thing in the world of computing. All for the right reasons, because there are several advantages to be had by implementing virtualisation.
Cost Savings – this is one of the major benefits which often cited as a reason for implementing virtualisation.
Firstly when you virtualise, you can cut down on computing equipment like the number of servers you employ. The net effect is a drastic reduction in the amount of energy your company uses. This represents a huge cost savings.
Secondly, by reducing the amount of computing equipment, you are eliminating the need for more space for such equipment. Real estate costs can be a significant part of your costs. Therefore when you do not need more space for equipment, you are saving money. Cost savings of between 50 – 70% have been quoted as typical when virtualisation is implemented.
Thirdly if you run your IT in-house, you will need to employ people to administer your systems. After virtualisation, the number of systems is greatly reduced and therefore your cost of system administration will be significantly cut down.
Simplification of IT – when you virtualize, you simplify your computing, by having for example various applications running on a single server.
Reduce or eliminate need for several upgrades – when you run multiple applications each on their own server, there is the need for you to always upgrade these systems each time there is a new patch for your systems. With virtualisation there is no need for you upgrading (if your systems are outsourced) or you will have fewer systems to upgrade.
Improve efficiency and availability of resources - When you virtualise, your computing efficiency is dramatically improved. You use much less energy as a consequence. One clear advantage of virtualisation is the reduction of energy consumption. When you use less energy, the amount green gas emitted into the atmosphere is reduced. Virtualisation is therefore rightly seen as one tool in the fight against global warming.
Your business is likely to recover more quickly from a disaster (if you were hit by one) when you have virtualized than when you run all your systems in-house.
Strategic advantage – many people nowadays are becoming environmentally aware. As a result more and customers and potential customers are now looking at the green credentials of companies they do business with. If you can present your company as an environmentally friendly company, taking the right actions to protect the environment, this is a plus and can be an advantage to you over your competitors.
To sum up - virtualisation will enable better system and hardware usage; it will curb data centre sprawl, reduce your IT administration cost, by reducing the number of physical machines you have to manage, contribute towards the fight against global warming by reducing the amount of energy you use, and give you a strategic advantage over your competitors.
Cost Savings – this is one of the major benefits which often cited as a reason for implementing virtualisation.
Firstly when you virtualise, you can cut down on computing equipment like the number of servers you employ. The net effect is a drastic reduction in the amount of energy your company uses. This represents a huge cost savings.
Secondly, by reducing the amount of computing equipment, you are eliminating the need for more space for such equipment. Real estate costs can be a significant part of your costs. Therefore when you do not need more space for equipment, you are saving money. Cost savings of between 50 – 70% have been quoted as typical when virtualisation is implemented.
Thirdly if you run your IT in-house, you will need to employ people to administer your systems. After virtualisation, the number of systems is greatly reduced and therefore your cost of system administration will be significantly cut down.
Simplification of IT – when you virtualize, you simplify your computing, by having for example various applications running on a single server.
Reduce or eliminate need for several upgrades – when you run multiple applications each on their own server, there is the need for you to always upgrade these systems each time there is a new patch for your systems. With virtualisation there is no need for you upgrading (if your systems are outsourced) or you will have fewer systems to upgrade.
Improve efficiency and availability of resources - When you virtualise, your computing efficiency is dramatically improved. You use much less energy as a consequence. One clear advantage of virtualisation is the reduction of energy consumption. When you use less energy, the amount green gas emitted into the atmosphere is reduced. Virtualisation is therefore rightly seen as one tool in the fight against global warming.
Your business is likely to recover more quickly from a disaster (if you were hit by one) when you have virtualized than when you run all your systems in-house.
Strategic advantage – many people nowadays are becoming environmentally aware. As a result more and customers and potential customers are now looking at the green credentials of companies they do business with. If you can present your company as an environmentally friendly company, taking the right actions to protect the environment, this is a plus and can be an advantage to you over your competitors.
To sum up - virtualisation will enable better system and hardware usage; it will curb data centre sprawl, reduce your IT administration cost, by reducing the number of physical machines you have to manage, contribute towards the fight against global warming by reducing the amount of energy you use, and give you a strategic advantage over your competitors.
Saturday, August 21, 2010
Desktop Virtualisation
One type of desktop virtualisation is to use your desktop device only to display data while all the processing and storage (applications & data) is done by back-end servers.
Your desktop device could be a traditional PC or a specialised device like SunRay virtual display Client.
To implement this type of desktop virtualisation, you need to run a virtual desktop infrastructure Software on the desktops.
There are several virtual desktop infrastructure Software like:
You could have a system running windows and you install this software which enables you run Linux on the same computer.
Your desktop device could be a traditional PC or a specialised device like SunRay virtual display Client.
To implement this type of desktop virtualisation, you need to run a virtual desktop infrastructure Software on the desktops.
There are several virtual desktop infrastructure Software like:
- VMware's Virtual Desktop Infrastructure.
- Sun VDI Software.
- Data is stored in a centralised location for easy management and is less likely to be lost or stolen.
- Huge amounts of savings from reduced desktop system administration.
- Reduced IT maintainance, upgrades, and threats from viruses and other malware.
You could have a system running windows and you install this software which enables you run Linux on the same computer.
Data/Storage Virtualisation
Managing disk storage was once simple: If we needed more space, we got a bigger disk drive. But data storage needs grew, so we started adding multiple disk drives. Finding and managing these became harder and took more time, so we developed RAID, network-attached storage and storage-area networks. Still, managing and maintaining thousands of disk drives became an ever more onerous task.
The latest answer to this dilemma is storage virtualisation, which adds a new layer of software and/or hardware between storage systems and servers, so that applications no longer need to know on which specific drives, partitions or storage subsystems their data resides. Administrators can identify, provision and manage distributed storage as if it were a single, consolidated resource. Availability also increases with storage virtualisation, since applications aren't restricted to specific storage resources and are thus insulated from most interruptions.
Also, storage virtualisation generally helps automate the expansion of storage capacity, reducing the need for manual provisioning. Storage resources can be updated on the fly without affecting application performance, thus reducing downtime.Thursday, August 19, 2010
Server Virtualisation
There are three types of server virtualisation - operating system virtualisation, hardware emulation & paravirtualisation.
Operating System (OS) Virtualisation - also known as "Containers" enables an operating system ("guest") to run on top a "host" operating system. The guest operating system makes the resources of the hardware on which it is installed available to the applications using it. The applications have no interaction with the host operating system. In fact according to these applications, they are the only one interacting with the hardware.
You can use this type of virtualisation (container virtualisation) to offer different operating systems to different users, with a single physical machine.
This is the ideal type of virtualisation for web hosting companies. They can host several different websites on the same physical machine, with each website having its own "container". To each website, they are in total control of the machine, but in reality they are sharing it with other websites.
One serious drawback of operating system virtualisation is that your choice operating system is limited depending on the host operating system.
Example operating system virtualisation:
Sun - Solaris Operating System.
Hardware Emulation
With this type of virtualisation, the virtualisation software also known as hypervisor serves up an emulated hardware environment for guest operating system to operate on. The emulated hardware environment is called a virtual machine monitor. I.e. the virtualisation software (hypervisor) "fools" the guest operating system, into thinking it has a real hardware environment on which to operate, by presenting it the virtual environment known as virtual machine monitor (VMM).
The hypervisor sits between the VMM and the physical hardware and acts as an interpreter between the two. Each guest OS runs on one VMM
This implementation implies multiple OS and also different types of Operating software can run on the same machine. For example you can run windows and Linux on the same machine or different versions of windows on the same physical machine.
Software development companies can use this type of virtualisation to test their software on different operating systems, without having to buy new machines for each operating system.
You can also use hardware emulation virtualisation to move your applications environments unto the same physical machine.
The major disadvantage of hardware emulation is that the hypervisor (virtualisation software) hurts performance, and you will often find that applications run slower on virtualized systems.
One other drawback is that since the VMM acts as an interpreter between the hypervisor and the physical machine, there is need for device drivers to be installed between the hypervisor and the VMM, however they is need to update these drivers from time to time. But the users are unable to install these devices. This might lead to a situation where some resources may not run on virtualized environment when there are hypervisor drivers for them.
Where to get hardware emulation virtualisation (hypervisor software):
VMware - VMware Server & ESX Server
Microsoft - VMware (supports X86 servers only, emphasis on MS OS), Hyper-V,
Xen - Open source alternative
Paravirtualisation
With a paravirtualisation implementation, the virtualisation software sits between the guest operating system and the resources of the physical machine. The virtualisation software controls access to the resources of the physical machine.
The main advantage of this implementation regime is that there is less performance overhead used. There is also no need for device drivers like is the case with hardware emulation.
It has its own drawbacks which include the fact that
Examples:
Xen from XenSource (found in Red Hat and Novell distributions
Virtual iron also from Xensource
Operating System (OS) Virtualisation - also known as "Containers" enables an operating system ("guest") to run on top a "host" operating system. The guest operating system makes the resources of the hardware on which it is installed available to the applications using it. The applications have no interaction with the host operating system. In fact according to these applications, they are the only one interacting with the hardware.
You can use this type of virtualisation (container virtualisation) to offer different operating systems to different users, with a single physical machine.
This is the ideal type of virtualisation for web hosting companies. They can host several different websites on the same physical machine, with each website having its own "container". To each website, they are in total control of the machine, but in reality they are sharing it with other websites.
One serious drawback of operating system virtualisation is that your choice operating system is limited depending on the host operating system.
Example operating system virtualisation:
Sun - Solaris Operating System.
Hardware Emulation
With this type of virtualisation, the virtualisation software also known as hypervisor serves up an emulated hardware environment for guest operating system to operate on. The emulated hardware environment is called a virtual machine monitor. I.e. the virtualisation software (hypervisor) "fools" the guest operating system, into thinking it has a real hardware environment on which to operate, by presenting it the virtual environment known as virtual machine monitor (VMM).
The hypervisor sits between the VMM and the physical hardware and acts as an interpreter between the two. Each guest OS runs on one VMM
This implementation implies multiple OS and also different types of Operating software can run on the same machine. For example you can run windows and Linux on the same machine or different versions of windows on the same physical machine.
Software development companies can use this type of virtualisation to test their software on different operating systems, without having to buy new machines for each operating system.
You can also use hardware emulation virtualisation to move your applications environments unto the same physical machine.
The major disadvantage of hardware emulation is that the hypervisor (virtualisation software) hurts performance, and you will often find that applications run slower on virtualized systems.
One other drawback is that since the VMM acts as an interpreter between the hypervisor and the physical machine, there is need for device drivers to be installed between the hypervisor and the VMM, however they is need to update these drivers from time to time. But the users are unable to install these devices. This might lead to a situation where some resources may not run on virtualized environment when there are hypervisor drivers for them.
Where to get hardware emulation virtualisation (hypervisor software):
VMware - VMware Server & ESX Server
Microsoft - VMware (supports X86 servers only, emphasis on MS OS), Hyper-V,
Xen - Open source alternative
Paravirtualisation
With a paravirtualisation implementation, the virtualisation software sits between the guest operating system and the resources of the physical machine. The virtualisation software controls access to the resources of the physical machine.
The main advantage of this implementation regime is that there is less performance overhead used. There is also no need for device drivers like is the case with hardware emulation.
It has its own drawbacks which include the fact that
Examples:
Xen from XenSource (found in Red Hat and Novell distributions
Virtual iron also from Xensource
Monday, August 16, 2010
How virtualisation works...
To understand how virtualisation works, it is better perhaps to look at the different types of virtualisation. Each works in a different way and is implemented differently.
There are three different types of virtualisation: Server Virtualisation, Data or Storage Virtualisation and Desktop Virtualisation.
There are three different types of virtualisation: Server Virtualisation, Data or Storage Virtualisation and Desktop Virtualisation.
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