What’s new

This release includes improved performance with asynchronous I/O streaming, storage migration enhancements, SQL updates, support for Windows performance counters, and support for UEFI guest VMs for Nutanix AHV. See the fixed and known issues for additional information about this release of Citrix Provisioning.

Note:

Use the most recent version of the Citrix License Server for the latest features. If you are upgrading from an existing version to the newest version, the most recent version of the license server is available by using the product software. When you do not upgrade to the latest version of the license server, the product license enters the 30-day grace period. For more information, see Licensing.

Improved performance with asynchronous I/O streaming

A target device previously served incoming operating system storage requests by traversing through three different layers (RAM cache, VHDX file, and network streaming) sequentially to complete a request. This traversing leads to less than optimal performance due to the latency introduced when waiting for sub-IO completion, before submitting a new sub-IO request.

This release includes updates to the Citrix Provisioning target device that supports asynchronous IO in all three layers of the provisioning model: RAM cache, the VHDX file, and network streaming, effectively improving performance by adding asynchronous IO functionality.

Important:

This feature provides better performance, but comes with higher, temporary memory consumption. Citrix recommends that you test this feature in a non-production environment to verify that the performance is favorable before deploying to production.

The following vDisk cache modes support asynchronous IO:

• Private or maintenance mode
• Cache in device RAM with overflow on hard drive
• Cache on server persistent

By default, this asynchronous I/O feature is disabled. To enable it, apply a registry to Citrix Provisioning target device based on one of the following scenarios:

• For a new installation of Citrix Provisioning: Apply the registry update after finishing the installation of Citrix Provisioning on the target device and before running the Imaging Wizard.
• For a vDisk upgrading a target device to this version of Citrix Provisioning, apply the registry update when the vDisk is in Private or Maintenance mode.

Note:

Reboot the target device to apply the registry change.

Apply the following registry change:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\CVhdMp\Parameters] “AsyncIO”=dword:00000001

Warning:

Editing the registry incorrectly can cause serious problems that might require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.## Storage migration within the same host

Citrix Provisioning improves storage migration within the same host by updating how Citrix Studio integrates OS storage within a VM. To use this functionality:

1. In Citrix Studio, set the delivery group, containing members the desired target devices, to maintenance mode.
2. Shut down all provisioned target devices.
3. Go to Configuration > Hosting and select the Host resource that you want to change. In Actions portion of the screen, click Edit Storage.
4. In OS, Temporary, and PvD Storages, uncheck the old storage. Changing the storage places the storage into Superseded status. Click Remove… to permanently remove it. Select the new storage you are going to use.

1. Go to the hypervisor and migrate the VMs to the new storage. Some hypervisors (ESX and VMM) have meta data for VMs. Move them also.
2. Disable maintenance mode on the delivery group.
3. Boot all the provisioned target devices.

Implementing UEFI guest VMs for Nutanix AHV hosts

This release of Citrix Provisioning allows you to implement a UEFI guest VM for Nutanix AHV hosts. The following prerequisites exist:

• The Citrix Apps and Desktops DDC are installed, along with the Nutanix plug-in.
• The Nutanix plug-in is installed in the Provisioning Server and Provisioning Console.

Note:

The VM should be set to UEFI before installing the OS.

To implement a UEFI guest VM for Nutanix AHV:

1. Create a master VM.
2. SSH into Nutanix Acropolis and run the following command: **acli vm.update uefi_boot=True**.
3. Mount the Windows and virtual ISOs and install the OS.
4. Install all Windows updates on the OS.
5. Join the OS to Active Directory.
6. Install Citrix Provisioning on the target device.
7. Run the Citrix Provisioning Imaging Wizard to create the target device record, vDisk, and other elements. Choose No to shut down the target device, rather than rebooting it at the conclusion.
8. Set the VM to boot from the ISO boot and PXE boot the VM. Select one of the following boot options:
   • ISO boot – mount a BDM ISO created from the Provisioning Console. SSH into Nutanix Acropolis and run the following command: acli vm.update_boot_device VM NAME disk_addr=CDROM BUS. For example, acli vm.update_boot_device testVM disk_addr=ide.0; this example assumes that the CDROM is bus IDE 0.
   • Network boot - SSH into Nutanix Acropolis and run the following command: **acli vm.update_boot_device mac_addr= , acli vm.update_boot_device testVM mac_addr=52:54:00:2c:ff:03**.
9. Start the VM and log into Windows to start the second stage of Imaging Wizard, imaging.
10. Create a VM. As in the master VM, repeat steps 2 and 7.
11. In the Provisioning Console, create a VM record for the snapshot VM using the VM’s MAC address. Assign the vDisk created in step 7 to this device record.
12. Boot the VM. Install the VDA, and restart if prompted. Shutdown when the installation finishes.
13. Create a snapshot of this VM.
14. In the Provisioning Console, set the vDisk to standard image mode. If the cache mode is Cache on device hard disk or Cache in device RAM with overflow to hard disk, the Citrix Virtual Apps and Desktops Setup Wizard prompts you to create a cache disk.
15. Use the Citrix Virtual Apps and Desktops Set Up Wizard to provision UEFI provisioning target devices using the created vDisk.

SQL basic availability groups

Citrix Provisioning improves SQL functionality for basic availability groups. A basic availability group supports a failover environment containing a single database. SQL basic availability groups are configured the same way as SQL Always-On High Availability groups, with the following differences:

• Limit of two replicas (primary and secondary).
• No read access on secondary replica.
• No backups on secondary replica.
• No integrity checks on secondary replicas.
• Support for one availability database.
• Basic availability groups cannot be upgraded to advanced availability groups. The group must be dropped and readded to a group that contains servers running only SQL Server 2016 Enterprise Edition.
• Basic availability groups are only supported for Standard Edition servers.
• Basic availability groups cannot be part of a distributed availability group.

Tip:

For multi-subnet environments, see Enable SQL Always On multi-subnet failover.

Active Directory-based activation

This release improves Active Directory functionality by updating how Microsoft Volume Licensing is configured for an individual vDisk. With this improvement you can specify that the vDisk uses no volume licensing.

Note:

When using the Microsoft Volume Licensing for a vDisk, consider that Key Management Services (KMS), Multiple Activation Key (MAK) and Active Directory-based activation (ADBA) cannot be used together.

To improve active directory-based activation:

1. In the vDisk Property screen, set the vDisk Microsoft Licensing property to None.
2. On the target device, use slmgr-dlv for a Microsoft image, and cscript ospp.vbs/dstatus for a Microsoft Office image.

Tip:

A known issue exists where VAMT displays errors about duplicate CMID entries for ADBA activated devices. This occurs although ADBA does not utilize CMID. ADBA, despite being similar to KMS, does not use CMID. Microsoft reuses KMS data when compiling CMID information. The image below illustrates a VAMT tool screen for ADBA. The Duplicate Client Machine ID report displays conflicts for duplicate CMID entries for those devices.

Support for Windows performance counters

Citrix Provisioning target devices now provide Windows performance counters for each storage tier:

• RAM cache
• VHDX file
• network streaming

Using these performance counters, you can monitor target device streaming IOPS, bandwidth usage, current RAM usage, and VHDX file size.

VDA installer update for provisioned master images

The Citrix Virtual Apps and Desktops environment allows you to install the Virtual Delivery Agent (VDA) on a virtual master image. Use this feature if you are configuring Citrix Provisioning or third party tools to provision virtual servers from that master image.

Note:

When creating targets for Citrix Provisioning, select Create a Master Image using PVS or 3rd Party Provisioning Tools. When you select this option, Machine Creation Services (MCS), including MCS IO, is not installed.

How do I?

Use How Do I? pages in the Citrix Knowledge Center for additional information related to configuration, networking, antivirus, or hypervisor related procedures. These pages are purpose-built to help resolve problems arising from the use of Citrix Provisioning.