XenServer 6.1

• Storage XenMotion - Storage XenMotion extends the existing XenMotion capability of moving running VMs from one host to another to now include the case where (a) VMs are not located on storage shared between the hosts and (b) hosts are not in the same resource pool.
• Live VDI Migration - Live VDI Migration allows system administrators to relocate a VM’s Virtual Disk Image (VDI) without shutting down the VM.
• Added support for the EMC VNX storage array through the inclusion of SMI-S.
• Link Aggregation Control Protocol (LACP) support - enables the use of industry-standard network bonding features to provide fault-tolerance and load balancing of network traffic.
• Source Load Balancing (SLB) improvements - allows up to 4 NICs to be used in an active-active bond. This improves total network throughput and increases fault tolerance in the event of hardware failures. The SLB balancing algorithm has been modified to reduce load on switches in large deployments.
• ARP/IP Spoofing, traffic sniffing prevention and IPset support – ensures the security and reliability of networks in environments with untrusted VMs.
• SCVMM Constrained Service Deployment Support - users can now manage their SCVMM services deployed in constrained environments, no longer requiring a network connection between the SCVMM server and the VMs running the services.
• Multi-Tenancy improvements - allows system administrators to restrict a VM to send and receive traffic on a specific MAC address and a number of IPv4 or IPv6 addresses, without relying on VLANs and switch management software. This increases security in environments where VMs cannot be fully trusted.
• VLAN Scalability improvements - removes a previous limitation which caused VM deployment delays when large numbers of VLANs were in use. This improvement enables administrators using XenServer 6.1.0 to deploy hundreds of VLANs in a XenServer pool quickly and efficiently.
• Emergency Network Reset - provides a simple mechanism to recover and reset a host’s networking, allowing system administrators to revert XenServer hosts to a known good networking state.
• IPv6 Guest Support - enables the use of IPv6 addresses within guests allowing network administrators to plan for network growth.
• Citrix XenServer Conversion Manager - enables batch import of VMs created with VMware products into a XenServer pool to reduce costs of converting to a XenServer environment.
• Vhostmd support – enables XenServer to become a certified and supported platform on which to run SAP application services.
• New Installation Mechanism for XenServer Tools - XenServer Tools are now delivered as industry standard Windows Installer MSI files. This enables the use of 3rd party tools to deliver and manage the installation and upgrade of the XenServer device drivers.
• GPU Pass-Through extended support – GPU pass-through enables a physical GPU to be assigned to a VM thus allowing applications to leverage GPU instructions in XenDesktop VDI deployments with HDX 3D Pro. The number of supported GPUs per host has been increased from 1 to 4.
• Increased performance and scale – The number of supported VMs per host has been increased to 150 for all workloads; time to boot large number of VMs concurrently (bootstorm) reduced by up to a factor of 6.
• Introduction of Automated vendor self-certification kit - an automated HCL certification kit has been delivered that can be run by 3rd parties to self-certify their hardware thus enabling a greater range of hardware to be certified on XenServer.
• Enhanced Guest OS Support - supported Ubuntu 12.04, CentOS 5.7, 6.0, 6.1, 6.2, Red Hat Enterprise Linux 5.7, 6.1, 6.2, Oracle Enterprise Linux 5.7, 6.1, 6.2. Experimental support for Windows 8 and Windows Server 2012.

XenServer 6.0

• XenServer enhanced performance and scale with increased host memory support of up to 1 TB of RAM per host. Now runs the Xen 4.1 hypervisor.
• Support a broader list of guest OS’s including full Ubuntu 10.04, Debian Squeeze, Oracle Enterprise Linux 6.0, SLES 10 SP4 and experimental support for Solaris 10 and Ubuntu 10.10.
• Simplicity and ease of use – StorageLink and Site Recovery are now fully integrated into XenServer and no longer requires a Windows VM. Integrate and manage Workload Balancing with a new Linux-based virtual machine and the XenServer installation has been reduced to 1 install media.
• Optimized for XenDesktop – with enhanced scalability and performance, IntelliCache makes XenServer the best choice for TCO and ROI for a XenDesktop deployment.
• Infrastructure-as-a-Service improvements – the Open vSwitch is now the network default for XenServer.
• Microsoft System Center integration enables XenServer to be managed using System Center VMM.
• Improved network architecture - enhancements to the distributed virtual switch include increased performance on 10Gbps networks and line-speed networking via SR-IOV.

XenServer 5.6 FP1

• Enhanced performance and scale with increased host memory support of up to 512 GB of RAM per host.
• IntelliCache optimizes XenServer for XenDesktop deployments by utilizing local storage for boot images and non-persistent data.
• Distributed virtual network switching enables better visibility into the network and provides distributed fine grained networking configuration and control policies.
• Delegated web based admin console – enables management of XenServer virtual machines from a based console and offers VM level delegation for end users to manage assigned virtual machines.
• Virtual machine protection and recovery protects VM memory and disk against failures. Setting regular snapshot schedules ensures that virtual machine disk and memory state is protected in the event of an outage.
• High availability restart levels for improved restart capabilities of the most mission critical virtual machines.

XenServer 5.6

• NEW XenServer Advanced Edition includes High Availability, Dynamic Memory Control and Performance Monitoring and Alerting.
• Citrix V6 licensing for a more consistent Citrix user experience.
• Increased host support limits include memory support of 256GB per host and support for 64 logical processors per host.
• Improvements to network performance allow for 16 NICs per host and initial SR-IOV support for NetScaler VPX.
• Increased virtual machine density for XenDesktop deployments running on XenServer.
• CPU masking enables live migration across a heterogeneous server hardware pool by allowing the hypervisor to report the CPU configuration expected by each VM rather than the actual specification of the CPU.
• Enhanced XenCenter broadens interface-based management capabilities and integrates StorageLink to enable virtual servers to fully leverage existing storage assets, to reduce storage needs and accelerate VM deployment.
• Dynamic memory control allows for automated live memory reconfiguration, enables over-provisioning of host RAM and can define host memory policies for VM memory usage.
• Dynamic workload balancing improves system and application performance by automatically and intelligently placing VMs on the most suitable host in the resource pool as resources needs change or new VMs are created. Placement of VMs is based on a set of user-defined rules, thresholds, application CPU requirements, available memory, and I/O utilization.
• Citrix StorageLink Site Recovery simplifies the setup and configuration of disaster recovery for Hyper-V VMs by integrating with array-based DR controls for replication, fail-over, and testing.
• Live memory snapshots and rollback capture both memory and disk state of live VMs and revert to previous guest states. Support also includes branches for parallel subsequent checkpoints based on a previous common snapshot.
• XenServer guest OS support now includes RHEL/CentOS/Oracle Enterprise Linux 5.4 and SLES 10 SP3.
• Lab Management now includes a self-service portal with on-demand access to a library of pre-configured environments, the ability to create, clone, edit and share work environments, and a notification system alerting IT administrators to add or change requests.
• XenConvert improves conversion performance, enables disks and volume during a P2V conversion, support for P2V conversion of targets with multiple disks/volumes and improved support for Linux V2V and VMware and Microsoft conversions.
• Consolidated backup adds revert capabilities to VM native disk snapshots and enables backup vendors to interface directly with XenServer.
• StorageLink now supports storage system support, Windows systems that are not hypervisor hosts, allows for volumes to be resized through the XenCenter or StorageLink CLI and PowerShell and allows for storage volumes that were imported to a VM to be detached.

XenServer 5.5

• Burton Group certifies XenServer as 100 percent enterprise production-ready. XenServer is one of only two hypervisor platforms in the industry that the analyst firm has recognized as meeting 100 percent of the required features for enterprise production.
• Active Directory authentication, configurable through XenCenter allows selected users XenServer management privileges without root credentials.
• Workload Balancing recommends ideal placement of VMs at start-up/resume and live relocation for host maintenance. Placement is based on maximizing host performance or host density.
• Backup enablement lets backup vendors interface directly with XenServer by utilizing a VSS Provider and makes snapshotting available on all platforms through LVHD implementation.
• StorageLink is now integrated within XenServer using the CLI interface.
• XenCenter enhancements include basic disk snapshotting functionality to allow for easy creation of non-VSS disk snapshots and new VMs or VM templates from the VSS snapshot. UI improvements provide better organization of views of VMs, pools, servers, storage repositories, snapshots and networks from a single location.
• Broader guest support includes SUSE Linux Enterprise Server 11 (32- and 64-bit); Debian 5.0 (Lenny, 32-bit); RHEL/CentOS/Oracle 5.3
• XenConvert now supports Open Virtualization Format packages (OVF) and VMware Virtual Disks (VMDK).
• Runs the Xen hypervisor 3.3 with an improved public reporting system (“bug tracker”) and a reduced Dom0 footprint.

XenServer 5.0

• NEW fully-functional free version changes the way Citrix delivers its server virtualization.
• High availability automatically restarts VMs if failure occurs at the hypervisor, guest or host level. Dynamic failure planning algorithms allow administrators to see how many hosts failures can be tolerated in the current environment without compromising services.
• Integrated Disaster Recovery enables regular backups of virtual machine metadata. When combined with SAN storage replication, this provides a fast way to migrate entire resource pools to another physical site and continue running services with little interruption. It also permits the use of storage repositories which include all of the metadata for VMs installed on them, permitting a “transportable VM” model across resource pools.
• NEW Dell EqualLogic arrays storage repository type supports fast-cloning, snapshots and high-performance LUN-per-VDI access by directly controlling the storage array.
• Broader Guest OS Support for Microsoft Windows: Server 2008 (32-bit and x64); Linux: SUSE 9 SP4 32-bit, SUSE 10 SP1, SP2 64-bit, RHEL 4.7 32-bit, RHEL 5.2 32-bit/64-bit, CentOS 5.2 32-bit/64-bit.
• XenConvert allows conversion a server or desktop workload from a single physical disk on a physical machine to a virtualized instance in either the Microsoft Virtual Hard Disk (VHD) format, Citrix Xen Virtual Appliance (XVA) format, or a XenServer virtual machine.
• Quiesced disk snapshots for backup/recovery of Windows VM available for NetApp and Dell EqualLogic SRs.
• Fibre Channel and iSCSI multipath support, configurable from within XenCenter, ensures that redundant storage links to an FC SAN or ISCSI SR permit link failures without loss of service.
• Storage Support for QLogic and Emulex 8GB Fibre Channel HBA devices, as well as bug-fixes and stability improvements for other HBA devices.
• Enhanced VM performance for XenApp workloads, updated paravirtualization drivers in Citrix tools and added Windows Server 2008 “enlightenments.”
• Built on Xen hypervisor 3.2.