ESX 4 FAQ

VMware ESX and ESXi FAQs

What is the difference between VMware ESX and VMware ESXi?

VMware ESX and VMware ESXi are both bare-metal hypervisors that install directly on the server hardware. Both provide industry-leading performance and scalability; the difference resides in the architecture and the operational management of VMware ESXi. Although neither hypervisor relies on an OS for resource management, VMware ESX relies on a Linux operating system, called the service console, to perform two management functions: executing scripts and installing third party agents for hardware monitoring, backup or systems management. The service console has been removed from ESXi, drastically reducing the hypervisor footprint and completing the ongoing trend of migrating management functionality from the local command line interface to remote management tools. The smaller code base of ESXi represents a smaller “attack surface” and less code to patch, improving reliability and security. The functionally of the service console is replaced by remote command line interfaces and adherence to system management standards.

Which hypervisor should I choose to deploy with VMware vSphere?

VMware ESXi is the next generation hypervisor architecture from VMware. VMware ESXi’s smaller code base and lack of reliance on a general purpose operating system make it the more reliable and secure choice. Its compact design allows it to be embedded in mainstream physical servers for simpler and faster deployments. VMware ESXi was also designed with simplicity in mind. Its menu-driven startup and automatic configurations make it the easiest way to get started with VMware virtualization.

VMware ESXi is the recommended platform for both new and existing customers. Future hypervisor releases will solely be based on this architecture. However, you should consider the following points before deploying ESXi or switching from ESX to ESXi:

• Make sure your hardware is supported on ESXi as the hardware compatibility list (HCL) is not identical to ESX. In general, VMware ESX has a larger HCL due to its support for legacy servers but expect support parity for ESX and ESXi on all new servers.
• Make sure that your third party management and back up tools are compatible with ESXi. Some of these tools have a dependency on the service console (COS) of ESX, which has been removed from the architecture of ESXi. VMware has developed alternative integration points for ESXi and is actively engaged with backup and management partners to help them make the transition from ESX to ESXi. Most major management or backup vendors such as IBM, BMC, CA, HP, EMC, Symantec and Veritas offer ESXi-compatible products but you should check with your third party vendor for the latest information on supported products and version numbers.

VMware ESX and VMware ESXi have different hardware compatibility lists (HCLs) which will continue to expand. You can also review the minimum hardware requirements to run either VMware ESX or ESXi.

What Operating Systems can I run on VMware ESX and ESXi?

VMware offers the broadest operating system support as compared to any other virtualization vendor. Guest Operating System compatibility is the same for equivalent versions of VMware ESX and VMware ESXi.

Are there any VMware ESX features that are not compatible with ESXi?

Some specific networking features are not available in VMware ESXi, primarily those requiring configuration through the Service Console.

Can I run virtual machines created by Microsoft Virtual Server, Microsoft Virtual PC, or VMware Server on VMware ESX or ESXi?

Yes. You can use the free VMware vCenter Converter to import virtual machines that were created using VMware Server, Microsoft Virtual Server, or Microsoft Virtual PC version 7 or higher. VMware vCenter Converter also supports conversions from sources such as physical machines and certain third party disk image formats. View the VMware vCenter Converter FAQs for further details.

How are VMware ESX and ESXi different than VMware vSphere?

As hypervisors that partition a physical server into multiple virtual machines, VMware ESX and ESXi are a core component of VMware vSphere. VMware vSphere is the industry’s first cloud operating system that drastically reduces ongoing costs and increases control over delivery of service levels while still preserving the flexibility to choose between any type of OS, application and hardware architecture. VMware vSphere offers organizations high availability and centralized management functionality that span across multiple ESX or ESXi hosts such as live migration, protection against hardware failures, power management, and automatic load balancing. Customers can choose to deploy either VMware ESX or VMware ESXi as part of the VMware vSphere suite. All the functionality of VMware vSphere is supported on both VMware ESX and VMware ESXi. In fact, VMware vSphere supports server resource pools that contain both hypervisors.

How do I use VMware vCenter Server to manage my VMware ESX or ESXi hosts?

VMware vCenter Server provides centralized management for VMware ESX and ESXi hosts and their virtual machines. To manage an ESX or ESXi host with vCenter Server, you must have a vCenter Server Agent license, which is included in all editions of VMware vSphere. Thus, your ESX or ESXi host must have a VMware vSphere license for centralized management with vCenter Server.

Can I buy VMware ESX and ESXi preinstalled on servers?

Only VMware ESXi is preinstalled on select x86 servers. In fact, VMware ESXi is the industry's first hardware-integrated hypervisor. Dell, IBM, HP and Fujitsu-Siemens have already started shipping server units with ESXi embedded. Several other OEMs such as NEC and Fujitsu have announced that they will soon start shipping servers with ESXi embedded. View the hardware compatibility list of the server models that have VMware ESXi embedded.

Is it possible to download a virtual appliance into a VMware ESX or ESXi environment for evaluation?

Yes. If you are running VMware vSphere 2.5 and later along with ESX or ESXi 3.5 or later, it is possible to access a list of downloadable virtual appliances for evaluation into an ESXi environment. To access that list of virtual appliances, open your VMware vSphere client, select "Virtual Appliance" from the file menu, and then select "Import...". When you select “Import from the VMware Virtual Appliance Marketplace” and click “Next”, you will be sent to a page where you can download the appliances.

What is the difference between VMware ESXi and VMware Server?

VMware ESXi is an enterprise-class hypervisor that offers a bare-metal architecture for near-native performance, features like memory de-duplication to increase consolidation ratios, and a high performance cluster file system for managing VM files on shared storage. VMware ESXi and VMware ESX are the critical foundations for a dynamic and flexible virtualized datacenter.

VMware Server installs as an application on Windows or Linux, relying on the operating system for resource management. This limits its performance and scalability. VMware Server is popular for test and development activities. Virtual machines created using VMware Server can run on VMware ESXi, but they must first be converted using the free VMware vCenter Converter.