Disaster recovery backup and redundancy

Depending on how crucial the applications associated with your licenses are, you might want to create backup License Servers. Although Citrix stores backup copies of your licenses, downloading many replacement licenses can be time-consuming. If the License Server fails, you can store backup licenses on a network file share, or have a configured backup License Server ready.

You can use the same licenses for your disaster recovery site that you use for your production environment.

• Configure and manage your disaster recovery environment independently of your production environment.
• Don’t use both the production and backup License Servers to service license checkouts at the same time.
• Make only one License Server accessible at any one time
• The License Server in your disaster recovery environment must have an identical host name to the License Server in your production environment.

When the License Server is offline for maintenance activity

The standard 30-day License caching mode allows your systems to continue to function without degradation of performance or denial of service to support License Server maintenance requirements.

What can I do if my License Server is unrecoverable?

When you have a backup copy of your license files available, you have 30 days to do the following:

1. Rename an existing server in your environment to have the identical host name as your original License Server.
2. Install the License Server component and your backup license files to relicense your environment.

What can I do if my License Server is unrecoverable and I do not have a backup copy of my license files immediately available?

When you don’t have a backup copy of your license files immediately available, you have 30 days to access your My Account > Manage Licenses portal at Citrix website. To relicense your environment, do the following:

1. Download your license files.
2. Rename an existing server in your environment to have the same host name as your original License Server.
3. Install the License Server component and the license files you downloaded.

What can I do if my License Server is unrecoverable and I cannot rename an existing server in my environment?

When you can’t rename an existing server in your environment, you have 30 days to relicense your environment. Do the following:

1. Identify another server in your environment.
2. Install the License Server component.
3. Access your My Account > Manage Licenses portal at www.citrix.com.
4. Return and reallocate your license files using the host name of the new server you selected.
5. Download and install these license files.

Does any failure of the License Server degrade performance or deny service to users?

No. The 30-day License caching mode prevents you from experiencing degradation in performance and denial of service to users.

Redundancy solutions

Setting up redundancy solutions might be necessary only in mission-critical environments. For smaller or less mission-critical deployments, you can back up your License Server by creating a duplicate License Server and store it on or off the network.

You can ensure redundancy for your mission-critical environments by:

• Creating a clustered License Server. For more information about clustering and licensing, see Setting up the License Server on a Microsoft Cluster.
• Using the high availability feature on XenServer minimum release version 5.6.
• Duplicating the License Server and its contents. Give the duplicate computer the same name as the active License Server and store it off the network.
• Storing another License Server that has a different server name on the network. In this case, when the active License Server fails, you must change the backup server name to start using it as the active License Server.
• Using a network appliance. If you are using only one License Server to service license requests at any time, you can use a network appliance that detects server or network outages and route traffic to a backup License Server.

All methods let you exchange one server license for another without a loss of service, provided the exchange occurs within the License caching mode. For more information, see License caching mode.

Remember these key points:

• Because license files reference the server specified during allocation, you can use the files only on a server that has the same binding information. That is, the server name or FQDN or MAC address (possibly displayed on the portal as an Ethernet address) as the original License Server.
• You cannot have two License Servers that have the same name on your network active at the same time.
• Add any other licenses that you download to both the active License Server and the backup License Server.