Host Server Limits

• VMware vSphere has a total of 120 (hundred and twenty) virtual machines per host with the RAM per host being at 2048 GB with a total of 2048 virtual disks per host.
• XenServer has a total pack of 75 (seventy five) virtual machines per host with a RAM of 1024GB per host and 512 virtual disks per host.
• Both systems have 160 (hundred and sixty) logical CPUs per host with the VMware capable of having a total of 2048 Virtual CPUs per host. However, XenServer does not have any virtual CPUs on the host. 

Virtualization Management features:

• The only key management feature that is supported by both software programs is Thin Provisioning.
• While VMware does not support Asset Management and Configuration Mapping, XenServer does support these two management features in addition to Thin Provisioning but does not support key features such as Dynamic Resource Allocation, Failover and Live Migration. These three important features are on the other hand fully supported by VMware vSphere ESXi.
• It should be noted though that if you are looking for other additional features such as Automated Workflows, High Availability (HA), Maintenance Mode, Shared Resource Pools and VM Backup / Restore then it is advisable to try out other software programs such as VMware vSphere Essentials.

Supported Host Operating Systems

The next area that differentiates the two is supported host operating systems. Without a doubt, the Achilles heel of VMware vSphere is the number of host operating systems supported by the program.

• VMware vSphere does only support MS DOS and Free BSD as hosts.

• On the other hand, Citrix XenServer does support a plethora of host operating systems such as Novell Linux Desktop, Red Hat Enterprise Linux AS, Linux ES, Linux WS and Red Hat Linux. Other OS supported include Windows 2000 Professional and Server, Windows 98 and 95, Windows Me, Windows NT Server, Windows NT Terminal Server, Windows NT Workstation, Windows Server 2003 Enterprise, Web and Standard Editions and Windows XP Home and Professional editions.

Supported Guest Operating Systems

On this front, the Citrix XenServer vs. VMware vSphere ESXi battle is relatively even as they both support the following guest operating systems: Novell Linux Desktop, Red Hat Enterprise Linux AS, Red Hat Linux ES, Red Hat Linux WS ,Red Hat Linux, Windows 2000 Professional , Windows 2000 Server, Windows 98 , Windows 95, Windows Me, Windows NT Server, Windows NT Terminal Server, Windows NT Workstation, Windows Server 2003 Enterprise, Windows 2003 Web , Windows 2003 Standard, Windows XP Professional, and Windows XP Home Edition.

The exception, however, is that VMware supports MS DOS, Sun Java Desktop System and Solaris x86 platform edition as guest operating systems, while Citrix XenServer does not support any of these three operating systems either as host or guest operating systems.

Technical Support:

Both these software packages support a variety of technical support media such as forums, instructional videos, online self-service, knowledge base, system upgrades, telephone, and white papers.

They also differ in this area as VMware does not provide technical support via blogs, brochures, email, and owner’s manual but most importantly does have a well-staffed help desk and also offers a remote training option. 

Citrix XenServer on the other hand does provide technical support through blogs, email, brochures, and user’s/owner’s manual—but does not provide this support through a help desk or through remote training.

Conclusion

Coming to market presence and recognition space, the VMware vSphere ESXi seems to win out over its competitor. Now that you know more about both products, you can determine which best fits within your career path. 

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