ESXi
Pros: Excellent performance; easy installation; small 32MB footprint
Cons: Somewhat limited hardware support
Rating: 5 of 5 stars
Price: Free download
Recommendation: ESXi is the virtualization platform of choice for businesses of all sizes if you need to run a mix of Linux and windows VMs.
Company name: VMware Phone number: 877-486-9273 URL: www.vmware.com

Recently I tested VMware's free hypervisor-based virtualization product, ESXi. Announced at the 2008 VMworld conference, ESXi shares the same hypervisor and core virtualization code as VMware's flagship virtualization product, ESX Server. ESX Server has long been the undisputed champ of the enterprise IT virtualization marketplace and is sold only as a part of VMware’s Virtual Infrastructure 3 suite. Like ESX Server, ESXi supports a wide variety of Windows and Linux guest OSs and shares the same maximum capacities. On the host side, ESXi supports up to 32 host processors and 256GB of RAM. Virtual machine (VM) guests can have up to four virtual CPUs and 64GB of RAM. Although ESXi is free, if you want official VMware support you still need to pay for it.

The big difference between ESX Server and ESXI is in the service console. ESX Server includes a Linux-based service console running in the parent partition that’s used for a variety of command-line management operations. ESXi disposes of the management console, which pares its size down to just 32MB. Management is performed from a networked system using VMware’s Virtual Infrastructure Client (VIC) or from the remote command-line interface. The lack of the built in service console also means that ESXi lacks the web management interface that ESX Server has. Although in practice you typically perform all management using the VIC. The ESXi parent partition presents only a very Spartan menu that’s used for initial system configuration and powering on and off the server. ESXi’s small footprint helps to make it more secure by reducing the potential attack surface.

ESXi doesn’t run on all hardware, so you need to be sure your server will support it. You can view the supported systems at VMware's website. I installed and tested ESXi on an HP ProLiant ML370 G5, a rack-mounted 4U server. The system had two Intel Quad Core Xeon processors running at 1.86GHz on a 1066MHz front-side bus. The ML 370 G5 came equipped with 8GB of RAM and eight 72GB 15,000rpm drives configured as a RAID array. VMware touts ESXi as a 32MB installable and in keeping with this small size, the product was offered on a USB flash drive at VMworld.

The ESXi installation used a simple character-based interface. The installation was quick and easy, taking about five minutes, including the time to initialize the storage. After the installation was complete, I rebooted the server and used the ESXi configuration menu to set up the server’s name, root password, and management IP address. The entire system setup was done in less than 10 minutes.

ESXi’s system console is easier to use but more limited than ESX Server’s command-shell console. Like Microsoft Hyper-V Server 2008, ESXi lets you perform system setup tasks by selecting menu options. Also like Hyper-V Server, you can’t use the console to create or manage VMs.

After the initial server configuration is completed, you manage VMs on ESXi using the Virtual Infrastructure Client (VIC), which is installed simply by pointing your browser to the ESXi server’s IP address, clicking the download link, then running the VMware-viclient.exe installer. VIC provides a functional, full featured management console. However, the ability to perform such tasks as cloning VMs is missing unless you have VMware vCenter Server (formerly VMware VirtualCenter Server) installed. The VIC console is particularly useful as it consolidates management information. In addition to letting you manage VMs, users, and groups, it also displays a management event log and monitors CPU, memory, disk, and network utilization as well as CPU core temperature.

To gauge the performance of ESXi, I ran the same test suite that I used earlier this year in our ESX Server versus Hyper-V comparison (see “Virtualization Shootout, Part 1,” InstantDoc ID 98879. ESXi was installed on the same server that I used in the earlier ESX Server tests. As you would expect, because both products share the same core code base, the performance delivered by ESXi was virtually identical to ESX Server 3.5.

VMware’s ESXi provides a production-proven virtualization platform that’s easy to install and manage. In addition, it’s manageable through VMware’s VI3 management platform, giving it the ability to use VMotion as well as VMware’s backup and high availability features when VI3 is present. Although ESXi provides similar performance to Hyper-V, it supports a much greater range of Linux guests. If you need to run a combination of Linux and Windows VMs in a production environment, ESXi is your first choice in virtualization products. ESXi is a free download that’s available from VMware's website