How to choose the best tool for your virtual infrastructure?

Virtualization is a very popular topic in the corporate IT community. It can be said that each company is carrying out some kind of virtualization project. According to a survey by research firm TheInfoPro, more than half of the new servers in 2009 used virtualization technology, compared to 30% in 2008.

In a way, virtualization is the world of VMware. Whether it's a storage area network (SAN) vendor, a server vendor, or a network vendor, they all have a connection to VMware. VMware's technology runs on more than one-third of the unified computing system devices that Cisco has deployed so far. Enterprise management platforms such as HP Insight are expanding capabilities and adding in-depth support for VMware to simplify and accelerate the management of large numbers of virtual machines. This is important because VMware technology ensures smooth operation, allowing you to manage virtual servers in a similar way that used to manage physical servers. Everyone already knows this approach, it reduces the burden of migration and helps get a faster return on investment.

Obviously, the most popular hypervisor is developed by VMware. The main advantage is that VMware technology is widely used. With the vCloud program, you can build your own dynamic data center running VMware vSphere and vCenter, and then automatically increase or decrease resources with an external cloud service provider. There are currently more than 1,000 cloud service providers participating in the VMware Virtualized project, and many other providers have adopted VMware's vCloud API.

In addition to VMware, there are two other viable alternatives on the market: Microsoft and Xen. The same survey by TheInfoPro claims that 24% of the new virtual servers use Microsoft Hyper-V; 30% chose "other virtualization technologies", which most likely means Xen or free Citrix XenServer. Each has its own advantages and disadvantages, each with its own more suitable application areas. VMware and Microsoft are not very compatible with each other, and Xen is very compatible with both.

Mainstream hypervisor

The core of server virtualization is the hypervisor, which is located on the hardware (directly as "bare metal" or on the operating system). The hardware is divided into multiple virtual machines to manage the interaction between the hardware and the virtual machine. There are currently three main options for server hypervisors: Microsoft Hyper-V, VMware (ESX and vSphere), and Xen (the open source hypervisor supported by Citrix).

Here are some general things to know when choosing a hypervisor:

1. VMware should be the first choice for every business, because the company has been in the virtualization field for more than a decade. No one doubts VMware's ability to provide reliable hypervisors and scalable management tools. It's impossible to develop a hypervisor with outstanding performance, reliability, scalability, and manageability overnight, so these are important features to consider in an enterprise computing environment.

2. Microsoft's Hyper-V is a relatively newcomer; from the success of SharePoint, I think that Microsoft's free distribution of any product with its server software is highly likely to be deployed by users. Like most of Microsoft's products, Hyper-V is not the best, I'm afraid it will never be the best, but it is bundled and pre-installed, so why not try it?

3. Xen is a good choice for companies that have budgeted for Linux servers. There is always a trade-off between cost and function/utility. In times of economic hardship, many companies are more willing to sacrifice functionality/utility to reduce costs than in the past. In addition, if your company's server infrastructure is highly dependent on Citrix, Citrix's support for Xen should be an important factor to consider when purchasing.

4. If your goal is to have dozens or hundreds of virtualized servers distributed across multiple sites and to build internal private clouds and external public clouds, the only practical choice at the moment is VMware vSphere. Because the product has good scalability and manageability. VMware currently dominates the high-end enterprise virtualization market.

Basic Details

Microsoft Hyper-V: Microsoft offers a limited version of Hyper-V for free, as well as various Hyper-V versions that come with Windows Server 2008. Hyper-V can support up to 8 CPUs and 1TB of memory on the host. Microsoft is committed to using virtual machines to increase the availability of applications and servers. An important feature is live migration, which is to migrate a running virtual machine from one Hyper-V physical host to another. The function does not interfere with the service. If your company uses Microsoft products, it might be wise to have a virtualization project try to use Hyper-V because you already have it.

VMware ESX: This is the most widely deployed hypervisor today (most virtualization professionals are familiar with a version of ESX). The latest version supports up to 64 logical processing cores per host, 256 virtual CPUs and up to 1 TB of memory; it can run a wide range of guest operating systems including Windows, Linux, Solaris and NetWare. Virtual machines can be booted from a local or shared SAN storage system. The VMware vStorage Virtual Machine File System (VMFS) is a clustered file system that allows multiple ESX hosts to simultaneously access a single virtual volume, paving the way for shared storage resources through Fibre Channel SAN, iSCSI SAN, or Network Attached Storage (NAS) The road.

VMware vSphere 4: vSphere 4 is more than just a hypervisor, it is a data center cloud computing platform based on VMware ESX. At the beginning of last year, vSphere delivery caused a commotion because it promised to control the virtualized cloud environment inside and outside the enterprise: realize management automation, dynamically allocate resources, and migrate running virtual machines between physical machines to avoid interference with services. For example, applications can use virtual cloud resources inside and outside the enterprise to automatically increase and decrease resources. An important factor to consider is that there are currently a large number of APIs and third-party add-ons, so the industry's support for vSphere will only grow stronger.

Xen: The Xen hypervisor uses an open source version that provides efficient and secure virtualization of x86, x86_64, IA64, ARM, and other CPU architectures. It supports a wide range of guest operating systems, including Windows, Linux, Solaris and multiple versions of the BSD operating system. Xen is a collaboration of engineers from more than 50 data center solution vendors, including AMD, Citrix, Dell, Fujitsu, HP, IBM, Intel, Mellanox, Network Appliance, Novell, Red Hat, Samsung, SGI, Sun, Unisys, Veritas, Voltaire and Citrix.

Xen is known for its low footprint and high performance, and does not have many of the same features as the other technologies mentioned in this article. You can add the Xen cloud platform to get advanced management features like VMware vSphere and Microsoft System Center Virtual Machine Manager.

A few key points for successful implementation

A clear reason for launching a virtualization project proves that the return on investment is large and the total cost of ownership can be reduced. First evaluate the current physical server environment. Previously, you increased resources by adding more physical servers, and now you can reduce the cost by consolidating physical servers into multiple virtual servers running on a single physical server. This not only brings the resources that are needed today, but also the benefits of using virtual platforms to increase and decrease resources more effectively in the future. There is also a desire to reduce the cost of business continuity projects because, unlike physical machines, virtual machines can be moved from one place to another.

However, be aware of the possible impact of licensing and support issues. After an application is running on a virtual server, the licensing policy may change, so think twice. Also, make sure the application is supported on the virtual platform; they need the expertise once they need the help of a technical support person.

Investing time and resources to plan for this major change in enterprise architecture. Virtual servers are different from physical servers, so policies, procedures, and concepts have changed accordingly. Needless to say, you should ensure that the physical system has the appropriate backup and archive. Try to know how much hardware each virtual server needs, and then make sure you allocate the resources. In particular, it is necessary to guard against "virtual machine sprawl", which means that the virtual environment can sometimes be expanded at will until it loses control and cannot be managed. Finally, understand how the timing of the virtualization project affects other IT projects and ensure that all other projects support virtualization.

Make sure the migration is as smooth as possible for the end user. The best ending is that no one even notices that you have virtualized it. To achieve this, it is necessary to monitor the performance and availability of the initially deployed pilot system. Upgrade your hardware if you want to meet your performance and usability goals.

Several advantages of virtualization

Virtualization can reduce the cost of low physical server utilization. Many companies procure servers with solutions that take into account future resource requirements—our application may now use 5% of the resources, but the server can meet the need to use 50% of resources in a few years. But this means that today you are saving money for the resources you need tomorrow; we know that the cost of technical resources will only get cheaper and cheaper, so this excess computing capacity is basically wasted. Running multiple virtual machines on a single physical machine allows IT departments to take advantage of this extra capacity.

Running multiple virtual machines on a single physical machine can also reduce the area of ​​the physical server in the data center. The reduced number of physical servers means less rack space, energy and cooling, and reduced administrative overhead.

Virtualization separates operating systems and applications from server hardware, providing greatly enhanced flexibility. You can add or subtract resources for a virtual machine without shutting down and disassembling the physical server. Remember the last pain of the application due to hardware failure? In a virtualized environment, just migrate the virtual machine where the application resides to different hardware. This flexibility allows for a more efficient expansion of the server environment as business needs increase.