Citrix Hypervisor and Its Role in VDI Solutions

What is Citrix Hypervisor?

As its name implies, Citrix Hypervisor is a hypervisor—a software component that separates the operating system and applications from the physical hardware. It’s able to run multiple guest operating systems and applications, commonly known as virtual machines (VMs), on one physical host. The hypervisor manages and presents hardware resources like RAM, CPU, and storage to each VM and acts as if it were the underlying hardware.

This hypervisor is, more specifically, a Type 1 hypervisor. In other words, unlike Type 2 hypervisors, which run on top of conventional operating systems (which in turn also run on physical hosts like Hyper-V), it runs directly on bare metal, i.e., the physical hardware itself. They’re known to be more efficient and powerful than their Type 2 counterparts.

How Citrix Hypervisor Works 

There are several components involved in delivering Citrix Hypervisor functionality. The key components are: 

Formerly known as XenServer

Some time ago, Citrix Hypervisor was known as XenServer. “Xen” is the name of the hypervisor technology first developed by the University of Cambridge and eventually improved by Citrix. Here’s the history of that process:

Sometime in 2003, about a year after the original Xen was publicly released, the main developers founded XenSource. XenSource was formed to market Xen as an enterprise product. However, in 2007, the company was acquired by Citrix. Citrix retained ‘Xen’ in its branding and named its Hypervisor XenServer. Citrix XenServer was then rebranded in early 2018 as part of Citrix’s unification plan to rename the majority of its flagship products.

Citrix Hypervisor vs. VMware Hypervisor

Both Citrix Hypervisor and VMware Hypervisor perform similar roles, however, with notable distinguishing features. The table below summarizes the primary differences between Citrix Hypervisor (whose current version is 8.2) and VMware Hypervisor (currently, VMware ESXi version 7.0).


Feature Citrix Hypervisor Vmware Hypervisor
Virtual CPUs per VM 32 256
Concurrent VMs per host 1000 1024
Logical processors per host 448 768
Concurrent protected VMs per host when you enable HA (High Availability) 500 500
GPUs per host 8 Not specified.
vGPU VMs per host 128 Not specified. VMware claims that vGPUs VMs per host largely depend on the server in use and the number of physical GPUs.


Feature Citrix Hypervisor Vmware Hypervisor
Host maximum RAM 5TB 16TB
VM maximum RAM 1.5TB 6TB
Video memory per VM Not specified. Citrix employs Dynamic Memory Control to handle video memory in VMs. 4GB


Feature Citrix Hypervisor Vmware Hypervisor
VM Disk 2TB 62TB
Concurrent active virtual disks (vDisks) per host 2048 2048
Storage repositories per host 400 256
Disk I/O throttling Yes Yes
VM live Migration Yes Yes
Overcommit resources No Yes
VM Replication supports Yes Yes


Feature Citrix Hypervisor Vmware Hypervisor
Physical NICs per host 16 32
Physical NICs per network bond 4 Not specified
Virtual NICs per host 512 2048
VLANs per host 800 Not specified.
Network bonds per host 4 Not specified.


Feature Citrix Hypervisor Vmware Hypervisor
Open-source Yes No
Bare metal Hypervisor Yes Yes
Host OS support It supports Unix-based OS such as Red Hat Enterprise Linux AS, Linux ES, Novell Linux Desktop, and most Windows OS, including Windows 2000 Professional and Server, Windows NT Terminal Server, and Windows Server 2003 Enterprise, among others. It only supports MS-DOS and Free BSD as hosts.
Guest OS support It supports most Windows OS and Linux support. However, it doesn’t support MS-DOS, Solaris x86, and Sun Java Desktop System. It supports most Windows OS and Linux support. It also supports MS-DOS, Solaris x86, and Sun Java Desktop System.
Thin provisioning Yes Yes
Asset management and configuration Mapping Yes No
Graphics support Citrix offers extensive support for graphics. VMware offers limited graphics support.
Dynamic Resource Allocation and Failover No Yes
Pricing and Licensing There are two editions: the Standard and the Enterprise Edition. The Standard Edition is an entry-level commercial offering. It is free, while the Enterprise Edition is a premium offering and is optimized for desktop, server, and cloud workloads. VMware requires licensing on a per-processor basis. However, VMware ESXi Free is open-source and not as powerful as Citrix’s Standard Edition.

Changes in Citrix Hypervisor LTSR

Citrix Hypervisor 8.2 was released three years after the XenServer 7.1. Here are a few additions and changes that were introduced between the two LTSR versions.

Parallels RAS: An All-in-One VDI Solution

Parallels® Remote Application Server (RAS) is a virtual desktop infrastructure (VDI) solution that enables businesses to publish applications, desktops, as folders and data, to any device. One of its key features is the ability to publish VDI desktops, which are virtual desktops hosted on virtual machines. These VMs are in turn hosted on hypervisors like Microsoft Hyper-V.

Parallels RAS supports most major hypervisors including hyper-converged technologies, including Microsoft Hyper-V, VMware ESXi, Scale Computing HC3 and Nutanix Acropolis. This flexibility reduces the barriers to entry for companies who wish to adopt virtual application and desktop delivery while also helping them avoid vendor lock-in. In addition, Parallels RAS supports multiple hypervisors under the same infrastructure, which provides the flexibility of leveraging existing or different infrastructures from a single pane of glass. If you’re looking for a Citrix alternative, Parallels RAS is an ideal solution.

Try your 30-day evaluation period of Parallels RAS and leverage multiple hypervisors,