15.6 Failback

A failback operation restores the business function of a failed production workload in its original environment when the business function of a temporary failover workload is no longer required. Failback is the next logical step after a failover; it transfers the failover workload to its original infrastructure or, if necessary, a new one.

Supported failback methods depends on the target infrastructure type and the degree of automation of the failback process:

  • Automated Failback to a Virtual Machine: Supported for VMware ESX platforms and VMware DRS Clusters.

  • Semi-Automated Failback to a Physical Machine: Supported for all physical machines.

  • Semi-Automated Failback to a Virtual Machine: Supported for Microsoft Hyper-V platforms.

The following topics provide more information:

15.6.1 Automated Failback to a VM Platform

PlateSpin Protect supports automated failback for Failback containers on a supported VMware ESXi Server or a VMware DRS Cluster. See Supported VM Containers.

To execute an automated failback of a failover workload to a target VMware container:

  1. Following a failover, select the workload on the Workloads page and click Failback.

    The system prompts you to make the following selections

  2. Specify the following sets of parameters:

    • Workload Settings: Specify the failover workload’s host name or IP address and provide administrator-level credentials. Use the required credential format. See Guidelines for Workload and Container Credentials.

    • Failback Target Settings: Specify the following parameters:

      • Replication Method: Select the scope of data replication. If you select Incremental, you must Prepare a target. See Initial Replication Method (Full and Incremental).

      • Target Type: Select Virtual Target. If you don’t yet have a failback container, click Add Container and inventory a supported container.

  3. Click Save and Prepare and monitor the progress on the Command Details screen.

    Upon successful completion, PlateSpin Protect loads the Ready for Failback screen, prompting you to specify the details of the failback operation.

  4. Configure the failback details. See Failback Details (Workload to VM).

  5. Click Save and Failback and monitor the progress on the Command Details page. See Figure 15-2.

    PlateSpin Protect executes the command. If you selected Reprotect after Failback in the Post-Failback parameter set, a Reprotect command is shown in the Web Interface.

Figure 15-2 Failback Command Details

Failback Details (Workload to VM)

Failback details are represented by three sets of parameters that you configure when you are performing a workload failback operation to a virtual machine. See Table 15-2 for information about parameter settings.

Table 15-2 Failback Details (Workload to VM)

Parameter Settings

Details

Failback Settings

Transfer Method

Select a data transfer mechanism and security through encryption. See Encryption of Data in Transmission.

Failback Network

Specify the network to use for failback traffic. This is a dedicated network based on virtual networks defined on your VM container. See Networking.

VM Datastore

Select a datastore associated with your failback container for the target workload.

Volume Mapping

If the initial replication method is specified as “incremental”, select source volumes and map to volumes on the failback target for synchronization.

Services/Daemons to stop

Specify the application services (Windows) or daemons (Linux) that are automatically stopped during the failback. See Service and Daemon Control.

Alternative Address for Source

Specify an additional IP address for the failed-over VM if applicable. See Requirements for Protection across Public and Private Networks through NAT.

Workload Settings

CPU

(VM containers using VMware 5.1, 5.5, and 6.0 with a minimum VM hardware Level 8) Specify the number of sockets and the number of cores per socket for the failback to virtual workload. It automatically calculates the total cores. This parameter applies on the initial setup of a workload with an initial replication setting of Full.

NOTE:The maximum number of cores the workload can use is subject to external factors such as the guest operating system, the VM hardware version, VMware licensing for the ESXi host, and ESXi host compute maximums for vSphere (see vSphere 5.1 Configuration Maximums).

Some distributions of a guest OS might not honor the cores and cores per socket configuration. For example, guest OSes using SLES 10 SP4 and OES 2 SP3 retain their original cores and sockets settings as installed, whereas other SLES, RHEL, and OES distributions honor the configuration.

Number of CPUs

(VM containers using VMware 4.1) Specify the required number of vCPUs (virtual CPUs) to assign to the failback to virtual workload. This parameter applies on the initial setup of a workload with an initial replication setting of Full. Each vCPU is presented to the guest OS on the VM container as a single core, single socket.

VM Memory

Assign the required RAM to the target workload.

Hostname, Domain/Workgroup

Specify the identity and domain/workgroup affiliation of the target workload. For domain affiliation, domain administrator credentials are required.

Network Connections

Specify the network mapping of the target workload based on the virtual networks of the underlying VM container.

Service States to Change

Specify the startup state of specific application services (Windows) or daemons (Linux). See Service and Daemon Control.

Post-Failback Settings

Reprotect Workload

Select this option if you plan to re-create the protection contract for the target workload after deployment. This option maintains a continuous event history for the workload and auto-assigns/designates a workload license.

Reprotect after Failback

Select this option if you intend to re-create a protection contract for the target workload. When the failback is complete, a Reprotect command will be available in the Web Interface for the failed-back workload.

No reprotect

Select this option if you do not intend to re-create a protection contract for the target workload. To protect the failed-back workload upon completion, you will have to re-inventory that workload and reconfigure its protection details.

15.6.2 Semi-Automated Failback to a Physical Machine

Use these steps to fail a workload back to a physical machine after a failover. The physical machine might be either the original infrastructure or a new one.

  1. Register the required physical machine with your PlateSpin Server. See Failback to Physical Machines.

  2. If there are missing or incompatible drivers, upload the required drivers to the PlateSpin Protect device driver database. See Preparing Device Drivers for Physical Failback Targets.

  3. Following a failover, select the workload on the Workloads page and click Failback.

  4. Specify the following sets of parameters:

  5. Click Save and Prepare and monitor the progress on the Command Details screen.

    Upon successful completion, PlateSpin Protect loads the Ready for Failback screen, prompting you to specify the details of the failback operation.

  6. Configure the failback details, then click Save and Failback.

    Monitor the progress on the Command Details screen.

15.6.3 Semi-Automated Failback to a Virtual Machine

This failback type follows a process similar to the Semi-Automated Failback to a Physical Machine for a VM target other than a natively-supported VMware container. During this process, you direct the system to regard a VM target as a physical machine.

You can do a semi-automated failback to a container, for which there is fully-automated failback support (VMware ESX and DRS Cluster targets).

You can also do a semi-automated failback for target VM platforms on Microsoft Hyper-V Server 2012 hosts.

To start the Hyper-V VMs on failover:

  1. In a text editor, modify each Hyper-V host’s /etc/vmware/config file by adding the following line:

    vhv.allow = "TRUE"

  2. In the vSphere Web Client, modify the failover VM Settings for the CPU:

    1. Under the Virtual Hardware tab, select CPU.

    2. In Hardware virtualization, select Expose hardware assisted virtualization to guest OS.

  3. In the vSphere Web Client, modify the failover VM Settings for the CPU ID:

    1. Under the VM Options tab, expand Advanced, then select Edit configuration parameters.

    2. Verify the following setting:

      hypervisor.cpuid.v0 = FALSE