The hypervisor is arguably the most important piece in the virtualization puzzle. It is this software that makes it possible for a single physical machine to run multiple operating systems, all the while managing the resources of the host hardware so everything goes smoothly in each virtual container. Pretty cool stuff.
VMware has become synonymous with the virtual trend. The brand name is attached to an impressive lineup of desktop, server and cloud management software applications designed to help IT professionals maximize their computing resources. VMware is still the market leader, but Hyper V is quickly emerging as a threat to the crown.
Recently, there has been a lot of talk how Hyper V is climbing the market ladder, while VMware is slowly in decline. Microsoft has made the kind of improvements to convince more organizations to invest in its hypervisor products and it has "virtually" been enough to put an entire industry on notice.
Monolithic Hypervisors
As hypervisors, VMware and Hyper V are so comparable it's scary. Having said that, there are some notable distinctions and they are baked into the design of each platform, which is where we'll find advantages and disadvantages for both platforms.
VMware products like vSphere and ESX are monolithic hypervisors. In a monolithic design, the hypervisor manages hardware access for each virtual machine. It contains the device drivers for all components those virtual machines must access, including input, network and storage devices. This configuration requires the drivers to be physically installed at the hypervisor layer, in addition to a special driver that controls access to those hardware components.
The biggest advantage of the monolithic design is that it does not require a host operating system. That's right. The hypervisor acts as the operating platform that supports all the virtual operating systems running on the hardware. One key benefit this configuration offers is superior performance as those operating systems behave like they are actually running on the physical machine. Virtual machine administration is also simplified because there is no need for a host operating system to provide access to tools that manage those environments.
Now to the drawbacks. Although monolithic hypervisors are heralded for their performance traits, they are prone to instability issues because of the device drivers directly incorporated into their layers of functionality. What this means is that if one driver is hit by an update, bug, or security vulnerability, the entire virtual architecture within that physical machine will be compromised.
Speaking of security, it happens to be one of VMware's most pressing challenges to date. The company provides access to the operating platform in its hypervisor products through APIs, which unfortunately, makes it possible for malware writers to insert malicious code and compromise all the virtual environments on the physical machine. VMware was put on serious notice when confidential source code from its ESX hypervisor was exposed by hackers.
Microkernelized Hypervisors
Microsoft's Hyper V software is a microkernelized hypervisor. This particular product has no device drivers at the hypervisor layer. Instead, those drivers are located in the partitions of the individual operating systems, where they run independently for each individual virtual environment. As a result of this configuration, Hyper V is able to enjoy some unique advantages over VMware.
While Microsoft products are associated with a long history of security concerns, security happens to be one of Hyper V's strongest selling points. Because the microkernelized does not allow API access to the hypervisor layer, hackers cannot compromise an entire machine by embedding a single piece of malicious code. They must instead, try to compromise each virtual machine on an individual basis.
Hyper V is also less vulnerable to stability issues. Since device drivers are running at the virtual level, updates, bugs, or other potential driver-related problems can only affect those individual virtual machines. As a result, the risk of the entire virtual infrastructure being impacted by the stability issues of a single virtual machine are significantly reduced.
But just like VMware's monolithic build, the microkernelized design subjects Hyper V to some notable disadvantages. Hyper V calls for an operating system to be installed so the hypervisor can provide hardware access to all other guest operating systems. This configuration leaves the entire virtual architecture vulnerable to downtime. For instance, if the host operating system crashes for whatever reason, all those guest operating systems and their virtual machines are going down with the ship.
Availability can also be a concern for Hyper V environments. Microsoft maintains security for its operating systems by distributing updates. This applies to the host operating system controlling all the virtual machines as well. As dedicated Windows users know, those crucial security updates require the system to reboot, which means that if the virtual machines are not migrated to another node in the cluster, they will suffer downtime during the rebooting process. System maintenance is common, but any downtime can be potentially detrimental when mission-critical applications are involved.
Choosing Your Virtualization Tool
It's clear to see that VMware and Hyper V are far from perfect. Both come with a set of compelling advantages that demand attention as well as disadvantages that can't be ignored. There really is no right or wrong, but there are two practical ways to base your decision: track record and compatibility.
Hyper V is coming up, but VMware is the industry leader with a long of history of allowing organizations to successfully deploy virtual environments. It's hard to go wrong with the type of reputation it has established over the years.
Similar to other Microsoft applications, Hyper V integrates seamlessly with many Windows products. For example, this hypervisor is an integral part of the new Windows 8 and Windows Server 2012 operating systems. With that integration comes familiar interfaces and features that dramatically simplify the process of virtualizing Microsoft workloads and managing Windows-based virtual environments.
VMware has become synonymous with the virtual trend. The brand name is attached to an impressive lineup of desktop, server and cloud management software applications designed to help IT professionals maximize their computing resources. VMware is still the market leader, but Hyper V is quickly emerging as a threat to the crown.
Recently, there has been a lot of talk how Hyper V is climbing the market ladder, while VMware is slowly in decline. Microsoft has made the kind of improvements to convince more organizations to invest in its hypervisor products and it has "virtually" been enough to put an entire industry on notice.
Monolithic Hypervisors
As hypervisors, VMware and Hyper V are so comparable it's scary. Having said that, there are some notable distinctions and they are baked into the design of each platform, which is where we'll find advantages and disadvantages for both platforms.
VMware products like vSphere and ESX are monolithic hypervisors. In a monolithic design, the hypervisor manages hardware access for each virtual machine. It contains the device drivers for all components those virtual machines must access, including input, network and storage devices. This configuration requires the drivers to be physically installed at the hypervisor layer, in addition to a special driver that controls access to those hardware components.
The biggest advantage of the monolithic design is that it does not require a host operating system. That's right. The hypervisor acts as the operating platform that supports all the virtual operating systems running on the hardware. One key benefit this configuration offers is superior performance as those operating systems behave like they are actually running on the physical machine. Virtual machine administration is also simplified because there is no need for a host operating system to provide access to tools that manage those environments.
Now to the drawbacks. Although monolithic hypervisors are heralded for their performance traits, they are prone to instability issues because of the device drivers directly incorporated into their layers of functionality. What this means is that if one driver is hit by an update, bug, or security vulnerability, the entire virtual architecture within that physical machine will be compromised.
Speaking of security, it happens to be one of VMware's most pressing challenges to date. The company provides access to the operating platform in its hypervisor products through APIs, which unfortunately, makes it possible for malware writers to insert malicious code and compromise all the virtual environments on the physical machine. VMware was put on serious notice when confidential source code from its ESX hypervisor was exposed by hackers.
Microkernelized Hypervisors
Microsoft's Hyper V software is a microkernelized hypervisor. This particular product has no device drivers at the hypervisor layer. Instead, those drivers are located in the partitions of the individual operating systems, where they run independently for each individual virtual environment. As a result of this configuration, Hyper V is able to enjoy some unique advantages over VMware.
While Microsoft products are associated with a long history of security concerns, security happens to be one of Hyper V's strongest selling points. Because the microkernelized does not allow API access to the hypervisor layer, hackers cannot compromise an entire machine by embedding a single piece of malicious code. They must instead, try to compromise each virtual machine on an individual basis.
Hyper V is also less vulnerable to stability issues. Since device drivers are running at the virtual level, updates, bugs, or other potential driver-related problems can only affect those individual virtual machines. As a result, the risk of the entire virtual infrastructure being impacted by the stability issues of a single virtual machine are significantly reduced.
But just like VMware's monolithic build, the microkernelized design subjects Hyper V to some notable disadvantages. Hyper V calls for an operating system to be installed so the hypervisor can provide hardware access to all other guest operating systems. This configuration leaves the entire virtual architecture vulnerable to downtime. For instance, if the host operating system crashes for whatever reason, all those guest operating systems and their virtual machines are going down with the ship.
Availability can also be a concern for Hyper V environments. Microsoft maintains security for its operating systems by distributing updates. This applies to the host operating system controlling all the virtual machines as well. As dedicated Windows users know, those crucial security updates require the system to reboot, which means that if the virtual machines are not migrated to another node in the cluster, they will suffer downtime during the rebooting process. System maintenance is common, but any downtime can be potentially detrimental when mission-critical applications are involved.
Choosing Your Virtualization Tool
It's clear to see that VMware and Hyper V are far from perfect. Both come with a set of compelling advantages that demand attention as well as disadvantages that can't be ignored. There really is no right or wrong, but there are two practical ways to base your decision: track record and compatibility.
Hyper V is coming up, but VMware is the industry leader with a long of history of allowing organizations to successfully deploy virtual environments. It's hard to go wrong with the type of reputation it has established over the years.
Similar to other Microsoft applications, Hyper V integrates seamlessly with many Windows products. For example, this hypervisor is an integral part of the new Windows 8 and Windows Server 2012 operating systems. With that integration comes familiar interfaces and features that dramatically simplify the process of virtualizing Microsoft workloads and managing Windows-based virtual environments.
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