Physical vs Virtual: Who wins in the battle of the servers?
In the battles of the servers, which comes out on top: physical or virtual? When setting up a new host, which should you choose? How should you decide? Both options have their strengths and weaknesses. Key factors include:
Performance
Physical servers can perform better than virtual machines with the same resources. A virtual host can provide the same specs as a physical server; however, the virtual host shares resources with all running VMs in the virtual environment. Chances are, the virtual server is spec’d to handle the load of all VMs at their peak, but this is not always the case. The performance of a physical server, on the other hand, is not dependent on other servers’ resource consumption.
Relocation
Physical servers can be moved and separated from other servers without much trouble. There is no importing/exporting of files to get the server to work elsewhere. It can simply be moved and connected again. Minor configuration may be necessary, but this can be completed on the virtual machine after it is imported to its new destination.
Footprint
Here’s one area where virtual servers come out on top! Virtual servers create less of a footprint than physical machines. The only space required is for the host(s), storage if not part of the host, and network equipment. This also leads to less power consumption as these devices are the only devices using power.
Maintenance
Maintaining physical servers can be time-consuming, requiring personnel to update firmware, replace and upgrade physical components and create new servers. If a new server is necessary, one needs to be purchased or requires repurposing an old one. Adding or replacing hardware requires downtime in most cases. There are some exceptions, such as hot-swappable drives, but in most cases the failed hardware is inside the server.
Virtual servers offer some maintenance pluses. Creating and editing a new or current server can be done in a few clicks without purchasing any new hardware. There are times when downtime is needed to add certain resources; however, there is no need to remove anything from the physical machine. This can be done remotely rather than having to be at the rack to make the component upgrades. Additionally, all VMs and hosts can be managed from a central interface. VMware, for example, allows management at the host level or through vcenter, which allows all hosts to be managed in one place. Running Windows updates or making software changes is much safer on a virtual server as well. Snapshots can be taken prior to making changes. Once the changes are tested, the snapshot can be deleted. If the server fails due to the software change, it can easily be rolled back to a point prior to the failure.
Recovery
Physical servers do not recover well from disasters. New hardware will need to be purchased and sit idle in case of a disaster or new hardware must be obtained to fix or replace the failed server.
So which type of server wins? Depends on your goals. If you need to mimic a particular environment or the server needs to have a specific set of resources that can never be affected by other machines, a physical server may be the best choice.
If, on the other hand, you choose virtual, you must next determine where the machine will reside and run. This could be on a local physical machine or in a centrally managed environment, such as VMWare ESXi. Below are some considerations when choosing whether to install your virtual machine locally or on a centrally managed server.
Local virtual machines reside and run entirely on a local host. All necessary files are part of or attached to that host. One example of this is a laptop running VMware Workstation. The local virtual machine points to a path on the local machine. It then runs and shares resources and hardware with that local host. Because of this, if the computer crashes or gets powered off, the server also gets shut off. But this also allows you to run the VM at another site or network. It does require the local computer to be running. If it’s powered off, the VM will also shut down and has the potential for corruption. While the virtual machine is active, it will share resources with the local host. This may cause the local host to perform sluggishly if there are not enough resources to run both.
A centrally managed environment resides on a host running virtualization software such as VMWare ESXi. The host provides a management interface and allows all the servers running on it to consume its resources. Since the virtualization software is typically light, almost all its resources are shared by the virtual machines. In a perfect situation, multiple hosts exist with enough resources to allow failover in the case that a host fails. Running a system in VMWare ESXi or another virtual environment does not provide the same flexibility as a local machine but does provide many other benefits. The server can remain powered on even when your computer is not on. Assuming the virtual environment has failover capabilities, it provides your host with extra protection against a failure that your local system does not. It may also have access to many networks, assuming they are configured on the physical hosts, as well as the ability to add resources without consuming them on your local system.
As you can see, choosing a new system involves a host (pun intended) of factors. Whether you have access to all the options that I talked about or not, use what you have available to you and choose the solution that works best for the current situation.
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