What’s new

About this release

XenServer 7.6 is a Current Release (CR). The Current Release model allows customers to consume new features at the earliest possible juncture. A Current Release contrasts with the Long Term Service Release (XenServer 7.1 LTSR), which guarantees stability in terms of the feature set within XenServer.

XenServer 7.6 is available in the following editions:

  • Enterprise Edition
  • Standard Edition
  • Free Edition

For information about the features available in each edition, see the XenServer Feature Matrix.

XenServer 7.6 is available to download from the XenServer Product Download page.

New features and improvements in XenServer 7.6

XenServer XenServer introduces enhanced features and functionality for application, desktop, and server virtualization use cases. All XenServer 7.6 features are available to all licensed Citrix Virtual Apps and Desktops (formerly XenApp and XenDesktop) customers.

Networking SR-IOV: Passthrough of Virtual Functions (Enterprise Edition)

XenServer can now use Single Root I/O Virtualization (SR-IOV) that allows a single PCI device to appear as multiple PCI devices on the physical system.

You can assign one or more NIC Virtual Functions to a VM, allowing its network traffic to bypass the virtual switch. When configured, each VM behaves as though it is using the NIC directly, reducing processing overhead, and improving performance.

For more information, see Using SR-IOV enabled NICs.

Thin provisioning for shared block storage - GFS2 (Enterprise Edition)

XenServer makes thin provisioning available to customers using block-based storage accessed through iSCSI software initiator or Hardware HBA. Thin provisioning is implemented by using GFS2.

Thin provisioning makes better use of the available storage by allocating disk storage space to VDIs because data is written to the virtual disk, rather than allocating the full virtual size of the VDI in advance. Thin provisioning enables you to significantly reduce the amount of space required on a shared storage array, and with that your Total Cost of Ownership (TCO).

The following use cases can benefit from thin provisioning:

  • Server virtualization
  • Citrix Virtual Apps and Desktops (both persistent and non-persistent)
  • Large-scale Cloud deployments

Thin provisioning for shared block storage is of particular interest in the following cases:

  • If you want increased space efficiency, because images are sparsely and not thickly allocated.
  • If you want to reduce the number of I/O operations per second on your storage array. The GFS2 SR is the first SR type to support storage read caching on shared block storage.
  • If you use a common base image for multiple virtual machines, because the images of individual VMs then typically use even less space.
  • If you use snapshots, because each snapshot is an image and each image is now sparse.

For more information, see Storage.

It is not possible to upgrade or update from the experimental version of the feature provided in XenServer 7.5 to the fully supported feature in XenServer 7.6. If you previously used this feature as an experimental feature, complete the following steps when updating to XenServer 7.6:

  1. Export any data that you want to keep from these SRs.
  2. Detach and destroy any GFS2 SRs from your pool before upgrading.
  3. Disable clustering on your pool.
  4. Complete the update to XenServer 7.6
  5. After the update completes, run the following command on all hosts in your pool:

    rm /var/opt/xapi-clusterd/db
    
  6. Run the following command on the pool master:

    systemctl restart xapi-clusterd
    
  7. When creating a GFS2 SR for your updated pool, ensure that you select Format and not Reattach. You cannot reattach a GFS2 SR that was created with XenServer 7.5 to a XenServer 7.6 pool.

Changes to guest operating system support

XenServer now supports the following new Linux guests:

  • Red Hat Enterprise Linux 7.5
  • CentOS 7.5
  • Oracle Linux 7.5
  • Scientific Linux 7.5
  • Ubuntu 18.04

For more information, see Guest operating system support.

Automatic application of hotfixes during upgrade or update

XenServer simplifies the hotfix application mechanism when upgrading your XenServer hosts or pools to a newer version. The enhanced Rolling Pool Upgrade and the Install Update wizards in XenCenter allow you to install available hotfixes when upgrading to a newer version of XenServer. This enables you to bring your standalone hosts or pools up-to-date with a minimum number of reboots at the end. You must be connected to the Internet during the upgrade process for this feature to work.

You can benefit from the automatic application of hotfixes feature when you use XenCenter issued with XenServer 7.6 to upgrade from any supported version of XenServer to XenServer 7.0 and later.

Note:

Rolling Pool Upgrade is an Enterprise Edition feature. Upgrading your XenServer hosts using the Rolling Pool Upgrade wizard is available for XenServer Enterprise Edition customers, or those who have access to XenServer through their Citrix Virtual Apps and Desktops entitlement.

Using the Install Update wizard in XenCenter to update your version of XenServer is available to all users of XenServer. For more information about XenServer 7.6 licensing, see Licensing.

New structure for the product documentation

The XenServer product documentation is now provided as an HTML documentation set.

  • Use the table of contents on the left to navigate to the information that you need
  • Use the search box in the top-right to search for specific information
  • See an outline of the information in each article in the ‘In this article’ box
  • Download all content as a PDF for offline viewing by using the ‘View PDF’ button

All information from the PDF guides is included in the new documentation structure. For example, content from the Installation Guide is available in the Install section and content from the VM User’s Guide is available in the VMs section. The main subjects in the Administrator’s Guide are not included in a separate ‘Administer’ section and are instead listed in the table of contents.

Support for new processors

The following processors are now supported in XenServer 7.6:

  • Intel Processor families E-21xxG/21xx (Coffee Lake S)

For more information, see the Hardware Compatibility List.

Installation options

XenServer 7.6 is available to download from the XenServer Product Download page in the following packages:

  • XenServer 7.6 Update ISO. Use this file to update an existing installation of XenServer 7.5 or 7.4 CR.
  • XenServer 7.6 Base Installation ISO. Use this file to create a fresh installation of XenServer 7.6 or to upgrade from XenServer 7.0 or 7.1 Cumulative Update 1.

Note:

  • If you use XenCenter to update your hosts, update your XenCenter installation to the latest version supplied on the XenServer 7.6 download page before beginning.
  • Always update the pool master before updating any other hosts in a pool.

The following table shows the available options if moving from an existing supported version of XenServer to XenServer 7.6.

Installed Version Update using XenServer 7.6 Update ISO Upgrade using XenServer 7.6 Base Installation ISO
XenServer 7.5 Yes No
XenServer 7.4 Yes No
XenServer 7.1 Cumulative Update 1 No Yes
XenServer 7.0 No Yes

Upgrade from XenServer 7.1 with CU 1 applied. Ensure that you update your XenServer 7.1 to the latest Cumulative Update before upgrading to XenServer 7.6.

Before beginning installation, review the System requirements and Installation and deployment scenarios.

Changing from the Long Term Service Release to the Current Release

If you’re running a XenServer LTSR, but want to take advantage of new features, you can decide to change to the XenServer CR stream. Using the XenServer versions from the CR stream requires you to adopt new CRs regularly to remain in support.

Move to this Current Release by upgrading from XenServer 7.1 Cumulative Update 1 LTSR.

Changing from the Current Release to the Long Term Service Release

If you’re running a XenServer CR, but instead want to move to a version of XenServer with a guaranteed and stable feature set, you can change to a XenServer LTSR. The latest XenServer LTSR is available to download from the XenServer Product Download page.

Move to the latest LTSR by creating a fresh installation of XenServer 7.1 Cumulative Update 1 LTSR.

For more information about LTSRs and CRs, see Citrix Virtual Apps, Citrix Virtual Desktops, and XenServer Servicing Options.

Licensing

Customers must upgrade their Citrix License Server to version 11.14 or higher to use all XenServer 7.6 licensed features.

For more information about XenServer 7.6 licensing, see Licensing.

Hardware compatibility

For the most recent additions and advice for all hardware compatibility questions, see the XenServer Hardware Compatibility List.

Interoperability with Citrix products

XenServer 7.6 is interoperable with Citrix XenApp and XenDesktop 7.15 (LTSR), and Citrix Virtual Apps and Desktops 7 1808.

XenServer 7.6 is interoperable with Citrix Provisioning 7.15 and 1808.

Citrix product names are transitioning as we unify our product portfolio. For more information, see https://www.citrix.com/about/citrix-product-guide/.

Localization support

The localized version of XenCenter (Simplified Chinese and Japanese) is also available in this release.

Product documentation

To access XenServer 7.6 product documentation, see XenServer 7.6 Product Documentation. For FAQ about XenServer, see Technical overview.

Documentation can be updated or changed after the initial release. We suggest that you regularly visit the Citrix Product Documentation to learn about updates.