Configure disaster recovery for high availability 编辑

Disaster is a sudden disruption of business functions caused by natural calamities or human caused events. Disasters affect data center operations, after which resources and the data lost at the disaster site must be fully rebuilt and restored. The loss of data or downtime in the data center is critical and collapses the business continuity.

The Citrix ADM 12.1 disaster recovery (DR) feature provides full system backup and recovery capabilities for Citrix ADM deployed in high availability mode. At the time of recovery, certificates, configuration files, and a complete backup of the database is available in the recovery site.

The following table describes the terms used while configuring disaster recovery in Citrix ADM.

Note: The primary site and DR site communicate with each other through ports 5454 and 22, and these ports are enabled by default. For more information on port and protocol details, see Ports.

Disaster recovery workflow

The following image shows the disaster recovery workflow, the initial setup before disaster, and the workflow after the disaster.

Initial setup before disaster

The image shows the disaster recovery setup before disaster.

The primary site has Citrix ADM nodes deployed in the high availability mode. To learn more, see High availability deployment

The recovery site has a standalone Citrix ADM disaster recovery node deployed remotely. The disaster recovery node is in read-only mode and receives data from the primary node to create data backup. Citrix ADC instances in the recovery site are also discovered but, they do not have any traffic flowing through them. During the backup process, all data, files, and configurations are replicated on the disaster recovery node from the primary node.

Prerequisites

Before you set up the disaster recovery node, note the following the prerequisites:

• To enable disaster recovery settings, the primary site must have Citrix ADM nodes configured in high availability mode.

• The standalone deployment of Citrix ADM in the primary site does not support the disaster recovery feature.

• The Citrix ADM HA pair (in primary site) and the standalone node (in DR site) must have same software version, build, and configurations.

Citrix recommends that you set CPU priority (in virtual machine properties) at the highest level to improve scheduling behavior and network latency.

The following table lists the minimum requirements to configure the Disaster Recovery node:

First time disaster recovery setup

• Deploy Citrix ADM in high availability mode

• Deploy and register the Citrix ADM disaster recovery node

• Enable and disable disaster recovery settings from the user interface

Deploy Citrix ADM in high availability mode

To set up disaster recovery settings, ensure that Citrix ADM is deployed in high availability mode. For information on deploying the Citrix ADM in high availability, see High availability deployment

Note

• Citrix ADM deployed in high availability mode must be upgraded to Citrix ADM release version 12.1.

• Floating IP address is mandatory to register disaster recovery node with the primary node.

Deploy and register the Citrix ADM disaster recovery node

To register the Citrix ADM disaster recovery node:

1. Download the .xva image file from the Citrix download site and import it into your hypervisor.

2. From the Console tab, configure Citrix ADM with the initial network configurations.

   Note

   The disaster recovery node can be on a different subnet.

   

3. After the initial network configuration is complete, the system prompts for login. Log on using the following credentials – nsrecover/nsroot.

4. To deploy the disaster recovery node, type /mps/deployment_type.py and press enter. The Citrix ADM deployment configuration menu is displayed.

   

5. Select 2 to register disaster recovery node.

   

6. The console prompts for floating IP address of the high availability node and password.

7. Enter the floating IP address and password to register the disaster recovery node to the primary node.

   

   The disaster recovery node is now registered successfully.

   

   Note

   The disaster recovery node does not have a GUI.

Enable disaster recovery settings from the Citrix ADM GUI

After the disaster recovery node is registered successfully, you can enable the disaster recovery settings from the Citrix ADM primary site user interface.

1. Navigate to System > System Administration > Disaster Recovery Settings.

2. On the Configure Disaster Recovery Settings page, select Enable Disaster Recovery check box, and click Apply Settings.

   

3. A confirmation dialogue box is displayed. Click Yes to continue.

   

   Note

   The time taken for system backup depends on the data size and the WAN (Wide Area Network) link speed.

   To disable the disaster recovery settings, clear the Enable Disaster Recovery check box and click Apply Settings.

   A confirmation dialogue box is displayed. Click Yes to continue.

   Important

   • It is the responsibility of the administrator to detect that a disaster has occurred on the primary site.

   • The disaster recovery workflow is not automated and the administrator has to manually initiate after the primary site goes down.

   • An administrator must manually initiate the process by executing a recovery script on the disaster recovery node at the recovery site.

   • If you upgrade the HA pair in primary site, you must manually upgrade the standalone node in the DR site.

   If you disable the Enable Disaster Recovery option and click Apply Settings, Citrix ADM does not allow you to select the Enable Disaster Recovery option again.

   The following error message is displayed, when you click Disaster Recovery Settings:

   

   To enable the DR node again, reconfigure the DR node for your high availability pair:

   1. Log on to the DR node using a hypervisor or an SSH console.

   2. Configure the DR node, by following the procedure available at Deploy and register the Citrix ADM disaster recovery node.

   3. Enable the disaster recovery option.

   For more information, see the Frequently Asked Questions.

Workflow after the disaster

When the primary site goes down after a disaster, the disaster recovery workflow must be initiated as follows:

1. The administrator identifies that a disaster has struck the primary site and it is not operational.

2. The administrator initiates the recovery process.

3. The administrator must manually execute the following recovery script on the disaster recovery node (at the recovery site): /mps/scripts/pgsql/pgsql_restore_remote_backup.sh

   

4. Internally, Citrix ADC instances are automatically reconfigured to send the data to the disaster recovery node that has now become the new primary site.

   The following image shows that the disaster recovery workflow after the primary site is struck with a disaster.

   

   Note:

   After you initiate the script at the DR site, the DR site now becomes the new primary site. You can also access the DR user interface.

Post disaster recovery

After the disaster has occurred and the administrator initiates the recovery script, the DR site will now become the new primary site.

Important

• If you have installed Citrix ADM 12.1.49.x or earlier releases, you get a grace period of 30 days to contact Citrix to rehost the original license on the Citrix ADM (at the DR site).

• For 12.1.50.x or later releases, the Citrix ADM license is automatically synchronized to the DR site (Not a requirement to contact Citrix for the license).

• Pooled license for the DR site is supported from 12.1.50.x or later releases. If you have applied pooled licenses for the instances, manually reconfigure the instances to the DR site.