Some companies are seeking for ways to migrate to Hyper-V due to the perceived cost savings, without realizing that the virtualization platform may not be appropriate for them.
Microsoft’s marketing system is so fine-tuned it can sell almost anything. In the software industry, Microsoft’s marketing department is simply unsurpassed. In early 80’s, the company was an underdog but through steady product improvement, aggressive pricing and smart marketing methods, it finally grabbed a lion share’s of the software market. For example, it beat Apple in the “OS cold war” and obliterated Netscape in the “browser war”. And since 2008, the company has been trying to dominate the virtualization market with the Hyper-V that came with the Windows Server 2008.
Microsoft was infamous for its tendency to crush the competition ruthlessly and virtualization may be another market it is adamant about dominating. But can Microsoft succeed? While Hyper-V is often believed to be more affordable than VMware, but unfortunately the reality begs to differ. In some cases, the migration to Microsoft’s virtualization platform may cause the loss of functionality and 3rd-party support. You should consider whether the lower licensing costs of Hyper-V worth these drawbacks:
- Inefficient live migration: Even the most dedicated IT staff wants to get their jobs done and get home on time. You shouldn’t deploy a platform that causes you to accomplish less. With Hyper-V, you need to live migrate one virtual machine at a time, which is time consuming if you have dozens or hundreds of VMs. Although. Live Migration is useful to help you move virtual machines without interruptions, it doesn’t allow you to make a simultaneous migrations. When applying an update, administrators may need triple time to move all virtual machines to another host. Fortunately, it’s quite rare for multiple VMs to fail over simultaneously on a 1GB Ethernet and Hyper-V 3.0 already offers concurrent Live Migration.
- Poor OS support: If your IT department is a mixed environment of Windows and Linux, a migration to Hyper-V may not be feasible because it only supports Windows, SUSE Linux, Red Hat Enterprise Linux and CentOS.
- Security issue: Hyper-V relies heavily on Windows Server 2008 and it creates a specific security issue. When a vulnerability is found on Windows; the IT department needs to patch all physical machines. Often, the team can patch them quickly enough before the exploit affects the network. However, if a physical host running Windows Server 2008 is infected, it would jeopardize all the virtual machines that are running under the host. Luckily, patching VMs running under Windows Server 2008 is much easier with WSUS. Some experts recommend to never use popular operating system when running virtual machines in a company. Since Windows is dominating the market, it is under a constant threat and eventually an exploit will hit your server. Running a hypervisor under a different operating system can isolate it from exploits and other external threats. Also under the Windows 2008, the Hyper-V occupies more than 2.5GB of disk, while hard drive is quite affordable today, the bigger footprint gives hacker sizable attack surface. It is actually possible to reduce the footprint by running Hyper-V on Windows Server 2008 R2 On the other hand Vmware ESXi only consumes about 100 Mb.
A traditional concern for Microsoft’s operating systems is the fact that all drivers are loaded in the primary partition. Although Windows Server 2008 is adequately stable, reliable and secure, a large number of hackers are trying to prove the rest of the cyber-criminal community that they are smarter than the rich software giant. Many users said that using vSphere offers peace of mind and a layer of security.
- Poor memory management: Microsoft folks often downplay this drawback, but for some IT professionals it is a show stopper. Adequate memory management is important to get a desired VM density in each host, as the idea behind virtualization is to cram as many as VMs without sacrificing performance too much. The Microsoft’s decision to place less focus on this area is flat-out ridiculous.
- The possible need for extra hosts: Microsoft recommends us to set up a standby server running to cover the primary host that serves virtual machines. The driving objective behind virtualization is to improve the efficiency of hardware usage and setting up another host in standby mode can be quite costly in the long run. It means, you’ll get more hosts to rack, cool, manage and patch. The idea of buying more hosts and their supporting items should discourage you to migrate to Hyper-V. However, if you some more money and space to spare, setting up spare host is certainly a good thing.
- Lack of priority restart: Administrators expect a higher level of automation in a virtual world; far surpass what they had in physical infrastructure. If you plan to go entirely virtual, it is often necessary to prioritize virtual machines by the order of importance and you need to make sure that more important virtual machines can recover from host failures much more easily. In an event that a host that’s running 100 VMS’s fails, you want to make sure the virtual infrastructure to restart your failed virtual machines in a specific order. For example, make sure DHCP servers, DNS servers and domain controllers come up before IIS, SQL and Exchange. It doesn’t make sense to do too many things manually if you have a virtual infrastructure in places. Unfortunately, clustered Hyper-V may cost your business plenty of time as it doesn’t support VM priority restart. VM start prioritization is only available on unclustered, standalone Hyper-V and you can decide when the virtual machine should boot up after you start the parent partition. There is actually a workaround on starting VMs in a host running Hyper-V on certain order; you can specify the priority value of each VM in the custom properties. A Powershell script can be used to collect names of inactive VMs in a specific host. By querying the VM’s priority value, it is possible to start VMs based on the value.
- Lack of redundant VMs: Fault tolerance can improve system availability to a level that is unheard of and it is one of the widely appreciated features of vSphere. The ability to execute primary and secondary virtual machines simultaneously can easily give you continuous high availability that you’ll never have in a physical infrastructure. The redundant system prevents interruption in service as the secondary virtual machine runs automatically when the primary virtual machine fails. Many businesses consider that it is a feature that they can’t afford to ignore and they won’t get this feature from Hyper-V.
- Unreliable hot hardware installation: Many vendors of physical infrastructure promised hot hardware installation, but many IT administrators probably never tries because adding or removing RAM or hard drive is believed to be way too risky. In a virtual system, adding more RAM, hard drive and peripherals is actually much safer. Many administrators confidently and safely perform hot installation to powered-on VMware’s VMs Unfortunately; Microsoft doesn’t strongly assure us that hot installation can be performed reliably on hosts running Hyper-V. However, if you’re running Hyper-V under Windows Server 2008 R2, it is possible to install SCSI disks when the VMs are running, to do this; you simply need to add virtual SCSI controllers. Unfortunately, you still can’t add or remove RAM.
- Fewer third-party tools: Third-party tools in a virtual system can provide us with new features and it goes without saying that most enterprise class users will gain significant benefits from them. A quick comparison of 3rd-party tools used by Hyper-V and VMware shows that the gap is quite significant and those who want to get more extended functions should choose VMware.
- Maturity issue: Maturity is an important factor in the software industry, for example the version 1.9 of an application often works more reliably than the newer version 2.0, because new bugs are usually introduced, when an application is rebuilt from the scratch. When developing a virtualization infrastructure, you should make a strategic decision about the maturity issue of Hyper-V, a decision that’s often has a far-reaching consequence, something that you can’t change half-way through the project. Make sure your platform has been field-tested and that the performance metrics reveal favorable results. However, some users reported that Hyper-V is rock solid and they show no performance and stability issues after years of use.
It’s true that Hyper-V is so much cheaper, but many features and better reliability of vSphere can save you time and money. When you weigh in all the factors, the benefits for lower cost may not be as straightforward. The purpose of this article is not to convince you that Hyper-V is a poor virtualization platform, but IT departments should consider whether a migration to Hyper-V really worth the effort. If your organization is planning to deploy and migrate to Hyper-V, make sure its possible drawbacks won’t affect your business significantly.