Meeting VMware’s hardware requirements can be a challenging and frustrating process. You can’t use just any hardware with vSphere. You must choose components that are listed in VMware’s Hardware Compatibility Guide.
The Hardware Compatibility Guide lists hardware components -- such as servers, I/O adapters and storage devices -- that are certified to work with vSphere. Hardware that’s not listed may work with vSphere, but there are no guarantees. And VMware will not provide support if it suspects problems related to unlisted hardware.
The complexity of VMware hardware requirements and the possibility that current equipment will not be supported in future vSphere releases may drive companies to Microsoft Hyper-V, which offers better hardware support. This article discusses the problems with vSphere’s hardware requirements and what VMware can do to ease hardware-selection issues for users.
Why VMware hardware requirements are so finicky
VMware vSphere is a true bare-metal hypervisor that installs directly on hardware, without the need for an underlying operating system. As a result, the device drivers must be included in vSphere for it to support certain hardware, and they are specifically adapted for the VMkernel. If there isn’t a driver for a certain hardware device, it won’t work with vSphere.
On the other hand, Hyper-V relies on the underlying Windows OS for device drivers, so any hardware device with a Windows device driver -- which means just about everything -- will work with Hyper-V.
Problems with VMware’s hardware requirements
The purpose of VMware’s Hardware Compatibility Guide is to provide a comprehensive list of hardware requirements for customers. Hardware vendors must follow a certification process to have their products added to the guide.
Most vendors take the time to certify a majority of their new hardware. After all, if their hardware isn’t in the guide, customers may choose another vendor’s hardware that’s listed instead. That said, most vendors don’t certify all their hardware.
Take servers, for example. Most hardware vendors certify only expensive models, forcing customers to buy more costly servers. This strategy in particular could drive small and medium-sized businesses to Hyper-V, because they typically have limited IT budgets.
Vendors claim that they don’t waste their time certifying lower-end hardware because there is less demand for cheaper vSphere servers. But it would be nice to have lower-cost options, and it shouldn’t take much time and effort to certify a few additional server models.
CPU requirements and future support
The strict VMware Fault Tolerance (FT) CPU requirements also cause problems. Even if a server is listed in the compatibility guide and has a Fault Tolerance-compatible CPU, the vendor must specifically certify the server for Fault Tolerance. Otherwise, VMware won’t support it.
The FT requirement is tied to the CPU rather than the server model. VMware publishes a Knowledge Base article that lists the processors and guest OSes that support VMware Fault Tolerance. As long as your server has a CPU model on this list, it will probably work with FT. But without the vendor’s certifying it, you have no guarantees that it will.
Dell and Hewlett- Packard, for example, have servers listed on the Hardware Compatibility Guide that aren’t certified for FT – despite some having FT-compatible CPUs. Most of HP’s ProLiant ML server models have FT-compatible CPUs, but the more expensive DL360 and above models are certified for FT. So if you want to use Fault Tolerance, you have to buy more expensive, rackmount servers. You could argue that FT is more of an enterprise feature, but there are situations where it would be desirable to have FT on cheaper servers.
One more frustrating problem is that there are no guarantees that current hardware will work with future vSphere releases. If a company buys servers that are certified to work with vSphere 4.1, it’s possible that the equipment will not support newer releases. Even if upgrades work just fine on your hardware, you won’t be supported if the vendor doesn’t certify your hardware. If the upgrades don’t work, you may experience a Purple Screen of Death when installing a newer release on older hardware.
Fixing the hardware-selection process
How can VMware fix this situation so existing vSphere users don’t get fed up with playing hardware roulette and switch to Hyper-V? For starters, the company can work more closely with hardware vendors to make sure vSphere supports more hardware. VMware can also streamline the hardware-certification process to make it easier for vendors to certify more hardware.
In addition, VMware should broaden vSphere’s native hardware support so it’s simpler to insert drivers for unsupported hardware. It would be nice if customers could make the hardware work without involving the vendor or VMware , which can take months to resolve. The bottom line is, VMware needs to make hardware support as broad and easy as it is on Windows.
Companies that want to virtualize shouldn’t have to worry about hardware support. Ideally, you’d just buy the hardware, install vSphere and start virtualizing without any hardware headaches. But when buying hardware for vSphere, you really have to do your homework to make sure every piece is supported.
There is nothing worse than buying hardware from a major vendor, only to find that you missed something and it’s not supported. Dealing with incompatible hardware can make it frustrating to work with a great product like vSphere. Most customers don’t like to gamble with investments in server hardware, and most of us would rather avoid playing hardware roulette.
About the author
Eric Siebert is a 25-year IT veteran with experience in programming, networking, telecom and systems administration. He is a guru-status moderator on the VMware community VMTN forums and maintains vSphere-land.com, a VMware information site.