Open topic with navigation

Failing over full-server jobs

When a failover condition has been met, failover will be triggered automatically if you disabled the wait for user option during your failover configuration. If the wait for user before failover option is enabled, you will be notified in the console when a failover condition has been met. At that time, you will need to trigger it manually from the console when you are ready.

1. On the Manage Jobs page, highlight the job that you want to failover and click Failover in the toolbar.
2. Select the type of failover to perform.
• Fail over live data—Select this option to initiate a full, live failover using the current data on the target. The source is automatically shut down if it is still running. Then the target will stand in for the source by rebooting and applying the source identity, including its system state, on the target. After the reboot, the target becomes the source, and the target no longer exists.
• Perform test failover—This option is like the live failover, except the source is not shutdown. This option is generally used if your target is a virtual server. In this case, take a snapshot of the virtual server prior to testing failover. After failover is complete, you can revert back to the snapshot. If your target is a physical server, you will have to rebuild it manually after the test.
• Failover from a snapshot—Select this option to initiate a full, live failover without using the current data on the target. Instead, select a snapshot and the data on the target will be reverted to that snapshot. This option will not be available if there are no snapshots on the target or if the target does not support snapshots. To help you understand what snapshots are available, the Type indicates the kind of snapshot.
• Scheduled—This snapshot was taken as part of a periodic snapshot. 
• Deferred—This snapshot was taken as part of a periodic snapshot, although it did not occur at the specified interval because the job between the source and target was not in a good state.
• User Request—This snapshot was taken manually by a user.
3. Select the how you want to handle the data in the target queue. You may want to check the amount of data in queue on the target by reviewing the Statistics or Performance Monitor.
• Apply Data in Target Queues Then Failover— All of the data in the target queue will be applied before failover begins. The advantage to this option is that all of the data that the target has received will be applied before failover begins. The disadvantage to this option is depending on the amount of data in queue, the amount of time to apply all of the data could be lengthy.
• Discard Data in Target Queues and Failover Immediately— All of the data in the target queue will be discarded and failover will begin immediately. The advantage to this option is that failover will occur immediately. The disadvantage is that any data in the target queue will be lost.
• Revert to Last Good Snapshot if Target Data State is Bad— If the target data is in a bad Double-Take Availability state, Double-Take Availability will automatically revert to the last good Double-Take Availability snapshot before failover begins. If the target data is in a good state, Double-Take Availability will not revert the target data. Instead, Double-Take Availability will apply the data in the target queue and then failover. The advantage to this option is that good data on the target is guaranteed to be used. The disadvantage is that if the target data state is bad, you will lose any data between the last good snapshot and the failure.

4. When you are ready to begin failover, click Failover.

   Because the Windows product activation is dependent on hardware, you may need to reactivate your Windows registration after failover. In most cases when you are using Windows 2003, you can follow the on-screen prompts to complete the reactivation. However, when you are using Windows 2008, the reactivation depends on your licensing type. If a Windows 2008 target comes online after failover with an activation failure, use the steps appropriate for your license type.

   • Retail licensing—Retail licensing allows the activation of a single operating system installation.
   1. Open the System applet in Windows Control Panel.
   2. Under Windows activation at the bottom of the page, click Change product key.
   3. Enter your retail license key. You may need access to the Internet or to call Microsoft to complete the activation.
   • MAK volume licensing—Multiple Activation Key (MAK) licensing allows the activation of multiple operating system installations using the same activation key.
   1. View or download the Microsoft Volume Activation Deployment Guide from the Microsoft web site.
   2. Using an administrative user account, open a command prompt and follow the instructions from the deployment guide to activate MAK clients. Multiple reboots may be necessary before you can access a command prompt. You may need access to the Internet or to call Microsoft to complete the activation.
   • KMS volume licensing—Key Management Service (KMS) licensing allows IT professionals to complete activations on their local network without contacting Microsoft.
   1. View or download the Microsoft Volume Activation Deployment Guide from the Microsoft web site.
   2. Using an administrative user account, open a command prompt and follow the instructions from the deployment guide to convert a MAK activation client to a KMS client. Multiple reboots may be necessary before you can access a command prompt.

   Some applications and hardware devices create and use software devices within the operating system, but they have the characteristics of a hardware device. For example, software RAID solutions are typically implemented in the operating system, however they are still designed to emulate a single piece of storage hardware. In these cases, the device will not be failed over because it appears to be a hardware device.

   You may experience issues following a failover if an application or server uses hard-linked files. For example, Windows 2008 Server Roles added after full-server protection has been established will not function after failover because the hard links related to the server role were not replicated. After updating server roles, a remirror should be performed.

   If your NICs were configured for network load balancing (NLB), you will have to reconfigure that after failover.