How to start your Server virtualization journey

Virtualization is not limited to medium-to-large network environments, and even small network environments can make management simple and cost-cutting through virtualization. If you're new to virtualization technology, how do you get started?

If there is a technology that can expand the computing environment arbitrarily, it must be virtualized. By running multiple virtual servers with a single physical server, you can reduce operational costs and make your business more efficient. Whether your business has two servers or 2000, you can benefit from virtualization in different ways, and better yet, it's not hard and cheap.

Even with a small infrastructure, application virtualization can make management simple and cost-effective by reducing the number of physical servers, reducing power consumption and cooling devices, and reducing server sprawl. When it comes to new business applications, you don't need to buy new hardware, just add a new virtual server.

Virtualization can reduce the number of servers

If your business has only one server, virtualization won't save you much, but if you have more than two servers, or if you have plans to scale up at any time, application virtualization can bring a different experience.

It's hard to buy a non-multicore server now, but many small businesses don't need much performance, and buying expensive servers to handle simple tasks is a waste of energy and more heat. But multicore servers make more sense for virtualization-each CPU has 4, 6, or even 12 cores, which determines that a multi-core server can host more virtual machines.

CPU: Choose a truck not to choose a sports car

The key to successfully applying virtualization in a small environment is to start with a physical server, where the physical server will run multiple virtual servers, although a physical server is hosting 10 of virtual servers, but it requires less CPU resources than you think.

By applying virtualization software-from VMware, Microsoft Hyper-V, Citrix XenServer, or others-you can run multiple virtual servers on a quad-core or six-core CPU. This is because many servers are currently running close to idle for most of the time, and when virtual machines perform tasks, they consume resources designed for CPU, memory, hard disk, and network I/O, and only a small subset of the virtual machines need to consume a lot of CPU resources. With this balance rule, multiple physical servers can be consolidated into one server.

However, this is not always the case, some specific servers, such as the database server, usually run a large load, in a smaller infrastructure is not suitable for virtualization. Virtualization takes into account the available hardware resources for hosts (host Server), as well as the characteristics of virtualization software and the requirements of virtual machines. It seems complicated to consider these factors at the same time, but fortunately, setting and pre-testing these requirements is not very difficult.

Multi-core processors are more suitable for virtualization

The first step when an enterprise wants to do a small virtualization project is to select the hardware, usually starting with a single server, so try to get the best possible combination of resources within the budget range. A good experience is to choose a more core, higher-frequency server as a physical host (host server), So if you choose between a 4-core CPU with a clock frequency of 2.93GHz and a 12-core CPU with a clock speed of 2.4GHz, it's best to choose the latter, because more cores are needed to transfer the virtual machine load faster. Like loading more cargo, you need a truck instead of a sports car.

Memory and storage as much as possible

　　memory and storage as much as possible

After the CPU is chosen, the next part to consider is memory. The virtual machines consume a lot of memory, so you need to increase the memory as much as possible and choose the memory as fast as possible. In the host, it is relatively easy to allocate more virtual CPUs to the virtual machine than the physical host, but it is not possible to allocate memory over the cross. A host with greater memory means that more virtual machines can be run. This is important for some hypervisor that do not provide shared memory functionality, and some hypervisor require a fixed amount of memory for each virtual machine that is fully allocated to the specified virtual machine. In any case, configure as much memory as possible for the host.

To configure as much memory as possible for a virtualized server

The third area to consider is storage, where a SAN or NAS may not be used to store virtual machine images in a small network environment and stored by physical hosts. In this case, the physical host's hard disk capacity is of course the bigger the better. Typically, with SATA interface drives, a RAID 5 or RAID 6 array can be built to meet demand, even though SAS drives can provide better storage performance, but are more expensive. If possible, verify that the physical host can support RAID 5 or RAID 6 arrays to ensure data security.

　　Network interfaces are also important

In addition to CPU, memory, and storage, another factor to consider in the physical server is the network interface. In many cases it is simpler to use one to two NICs to support the entire virtual server environment, but if your network switch supports multiple nic bonding or aggregation, you can use these features to increase the bandwidth of the virtual server, which is supported by many medium Ethernet switches.

Network bandwidth guaranteed by 4 Gigabit NICs

Without the functionality of network adapter aggregation, you need to specify a network interface for a very busy virtual machine, but in this case the resources of the physical interface are quickly exhausted. However, the Gigabit Ethernet interface is relatively inexpensive, so if possible, it is best to place four Gigabit Ethernet interfaces on a single server.

　　Redundant power supplies make "baskets" stronger

Physical host the last area to focus on is power, in general, the server can configure a single power supply, but if you plan to run some virtual machines on the physical host, you should invest in redundant power supplies. Virtualization technology is like putting all the eggs in one basket, so reinforcing the "basket" can guarantee the reliability of the whole system. If the budget allows, a second power supply should be added to the physical host.

With at least one multicore CPU, larger memory, and a RAID 5 or RAID 6 local disk array , you can basically form a physical host in a small virtualized environment. When the hardware platform is ready, it is time to set up the software.

Three free virtualization software

virtualization software : There are three types of free options

There are a number of free options on virtualization software, and it's a good time to try these first when it comes to virtualization technology. VMware offers a free product , "VMware Server", that can run on Windows and Linux systems. It is not directly on the hardware of the virtualization software, but to rely on the operating system , so it is not a good performance, but relatively easy to install and use. If you need a completely free virtualization scenario, you can install the Linux system on the physical server and install the Linux version of VMware Server. Of course, you can also install Windows Server 2003/2008, which requires license, and install the Windows version of VMware Server, but this requires a license fee.

VMware also has a free, physical hardware-based virtualization system, VMware ESXi, which provides the functionality of VMware paid virtualization products, but has some limitations on hardware. VMware provides a hardware compatibility list that provides a reference for users planning to use ESXi to see if the physical host meets the requirements. If the physical host lacks a driver that supports VMware ESXi, the ESXi feature can be severely impacted and not even run.

VMware ESXi Login Interface

In addition to VMware's virtualization software, Microsoft's Hyper-V is another option and is more suitable for Windows-based systems. Hyper-V is fundamentally not free because it requires a Windows Server 2008/R2 system, but Hyper-V provides a simple interface and can be well combined with Win2008. Purchasing a Windows Server R2 replica can support 4 Windows Server 2008 systems without the need for additional license. If your server is already running Windows Server 2008, then Hyper-V is an economical option.

Microsoft Hyper-V Console

In addition to VMware and Microsoft, other virtualization software, such as Citrix XenServer, can be selected. Its free version offers many features that are not available in the VMware Free Edition, such as multi-server management. XenServer is not "mainstream" like two other virtualization software, but it's a good choice-it's free to download and install, and it doesn't have to rely on OS and OS License.

Citrix XenServer

Virtualization reduces Risk

One of the great advantages of applying virtualization is that you have a "retreat" space where you can capture and save the real-time state of a virtual machine using the capabilities of a virtual server snapshot. If the virtual machine fails later, you can roll back to the snapshot and revert to a previously known good state. For example, a software upgrade or patching of a system may cause problems, and taking a snapshot of a virtual machine can reduce the risk of the system.

Before applying virtualization, you can use a relatively inexpensive server and try a few free virtualization software before making your choice. Testing with a multi-core desktop PC can be done before you buy hardware, as long as you have enough memory configured. Regardless of the final choice, once you start to virtualize, even if you have only a few servers, you can get a different experience from it.

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How to start your Server virtualization journey