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VSA Live Recovery Overview

The VSA agent offers multiple Live Recovery features.

  • Live File Recovery – allows Commvault software to break open a backup or snapshot copy of a virtual machine and recover individual files. This feature provides extended support for various file system types. Use this feature to reduce backup times without sacrificing the capability to recover individual files.
  • Live Recovery for Virtual Machines – provides the ability to start a virtual machine almost instantaneously while recovering it in the background. This provides an artificially enhanced RTO as we do not have to wait for the full recovery operation to complete before accessing the virtual machine.
  • Live Mount – allows to power up virtual machines directly from the backup copy without having to restore it or commit any changes. This allows access to the virtual machine for validation purposes, testing or application level recovery via the provided mining tools.
  • Live Sync – takes changed blocks from our standard VSA protection copy and overlays those blocks to a warm standby VM at an alternate location thereby providing VM level replication. Live Sync can be used to create and maintain warm recovery sites for virtual machines running critical business applications.

Not all VSA features are supported on all hypervisors. For more information on supported features for your hypervisor, refer to the Commvault Online documentation.

Live Mount

Expand Client Computer Groups | VSA instance | Right-click the desired VM | All Tasks | Live Mount

The Live Mount feature enables you to run a virtual machine directly from a stored backup. You can use this feature to validate that backups are usable for a disaster recovery scenario, to validate the content on the backup, testing purposes, or to access data from the virtual machine directly instead of restoring guest files. 

Virtual machines that are live mounted are intended for short term usage and should not be used for production; changes to live mounted VMs or their data are not retained when the virtual machine expires. The VM expiration period is set through a Virtual Machine policy.

When a live mount is initiated, an ESX server is selected to host the virtual machine, based on the criteria set in the live mount virtual machine policy. The backup is exposed to the ESX server as a temporary Datastore. The configuration file for the live mounted VM is updated to reflect the name of the new VM, disks are redirected to the Datastore, and network connections are cleared and reconfigured to the network selected for the live mounted VM. When this reconfiguration is complete, the VM is powered on.

Tip: Using Live Mount for update validation
Situation: You are about to apply updates to a critical system and are concerned about the impacts on the system.

Solution: Use Live Mount to power on the same system from the backups. Isolate it on its own network to avoid duplicate hostname and IP address. Install and validate the update.




To create the Live Mount Virtual Machine policy

1 - Right-click Virtual Machine Policies | Create New Policy.

2 - Select the hypervisor.

3 - Select Live Mount.

4 - Type a name for the policy.

5 - Define the maximum number of mounts per user.

6 - Define the maximum number of hours a machine can be mounted.

7 - Define a MediaAgent for the Live Mount.

8 - Click on Next to continue.



9 - Select the VSA client.

10 - Update vCenter information and select a Datacenter.

11 - Select the ESX server on which the VM will be registered and hosted.



12 - VM can be moved to a datastore on expiration instead of being deleted.

13 - Select the virtual network to use for the mounted VM .

14 - Check the box if you are restoring from physical machine (Virtualize Me).

15 - Specify the path for the 1-Touch media.



16 - Select the users allowed to mounted VM.

17 - Review the summary and click Finish to complete.


To Live Mount a virtual machine

1 - First refresh the datacenters information. Right-click the VMware instance | All Tasks | Refresh Datacenters.

2 - Leave boxes unchecked and click OK .

3 - The system will query the vCenter for datacenters information.



4 - From the vCenter client computer group | Right-click the VM | All Tasks | Live Mount.

5 - Either select the latest backup or a specific point-in-time.



6 - Select the Live Mount policy and define a VM name.

7 - Select a network configuration for the virtual machine.

8 - The VM can be mounted immediately or scheduled to be mounted.

9 - The Live Mount job will appear in the Job Controller.


Live File Recovery

Right-click the desired subclient or backup set | Click All Tasks | Browse and Restore | Virtual Server tab

Live File Recovery provides expanded file system support, including ext4, and enables live browse of backup data without requiring granular metadata collection during backups. This option supports restores of files and folders from backups of Windows VMs and of UNIX VMs that use ext2, ext3, ext4, XFS, JFS, or Btrfs file systems.

Live File Recovery can also be used to reduce backup times. This is a trade-off; using this feature reduces backup time but increases the time required to browse files and folders. It is only supported for backups to disk storage targets.

To recover files or folders from a backup, you can enable backup data to be mounted as a temporary NFS Datastore that can be used to browse and restore file and folders. The process is similar to an ISO file that you right-click and mount on a Windows computer. The operating system virtually mounts the ISO file and cracks it open to display the content. In the case of Live File Recovery, the Windows MediaAgent locates the virtual machine's blocks in the disk library. These blocks are presented to the Windows operating system through a virtual mount driver. The VM file system is then cracked open and the content is displayed in the console.

For Linux virtual machine, the file system cannot be mounted by the Windows MediaAgent. It requires a virtual Linux MediaAgent on which the File Recovery Enabler for Linux (FREL) component must be installed.

For Service Pack 6 and earlier, a Linux VMware template containing the MediaAgent and FREL (downloadable from Commvault cloud) needs to be deployed. Refer to the Commvault Online Documentation VMWare section.

Since Service Pack 7, simply deploy a Linux VM and install the MediaAgent code. If the system requirements are in place, the FREL component is automatically installed with the MediaAgent software.

Enabling or disabling the Live File Recovery method is achieved by the 'Collect File Details' backup option of a subcient. If it is check, traditional file recovery is used. If unchecked, Live File Recovery is used.

The default, for a new backup or schedule, is to use Live File Recovery.

If 'Collect File Details' was enabled, but you still want to use Live File Recovery, configure the following additional setting key on the VSA proxy:
nEnforceLivebrowse with a value of 1

Performing a Live File Recovery is achieved through the usual guest files and folders recovery screens. The difference is in the system mechanics.

Live VM Recovery

Right-click the desired subclient or backup set | Click All Tasks | Browse and Restore | Virtual Server tab

The Live Recovery feature enables virtual machines (VMs) to be recovered and powered on from a backup without waiting for a full restore of the VM. This feature can be used to recover a VM that has failed and needs to be placed back in production quickly, or to validate that a backup can be used in a disaster recovery scenario.

Basically, the disk library is presented to the virtualization environment. Then the VM is powered on from the disk library. While it runs, the VM get moved back into the production Datastore using a storage 'vMotion' operation. All these tasks are accomplished automatically by Commvault® software.




To execute a Live Recovery

1 - From the Browse and Restore option window | Full Virtual Machine.

2 - Select Full Virtual Machine.

3 - Click to View contents.



4 - Select the virtual machines to restore.

5 - Click Recover All Selected.



6 - Select the destination hypervisor.

7 - Select the Proxy Client to execute recovery.

8 - Select a datastore to redirect the writes while the machine is moved.



9 - Select the disk provisioning type and transport mode.

10 - Select to execute a Live Recovery and select a datastore to redirect writes during the vMotion operation.

11 - The VM Live mount recovery can start immediately or scheduled.


Live Sync

The Live Sync feature enables incremental replication from a backup of a virtual machine (source VM) to a synchronized copy of the virtual machine (destination VM).

The Live Sync operation opens the destination VM and applies changes from the source VM backups since the last sync point. It is important to understand that since it is achieved from the backups, Live Sync is not a real-time synchronization.

The Live Sync feature can initiate replication automatically after backups or on a scheduled basis (for example, daily or once a week), without requiring any additional action from users. Using backup data for replications minimizes the impact on the production workload by avoiding the need to read the source VM again for replication. Additionally, in cases where corruption on the source VM is replicated to the destination VM, users can still recover a point-in-time version of the source VM from older backups.

If no new backups have been run since the last Live Sync, the scheduled Live Sync does not run.

When using Live Sync, it is recommended to use an incremental forever strategy. Run a first full backup, which gets replicated to the destination. Then, only run incremental backups to apply the smallest changes possible to the destination. Periodically, such as once a week, run a synthetic DASH full backup to consolidate backups in a new full backup, without impacting the replication. If you execute a real full backup, the entire machine must replicate to the destination.

Live Sync Configuration

Right-click the desired subclient or backup set | Live Sync | Configuration

Before you configure Live Sync, configure the vCenter client in the CommCell® console. If the destination uses a different vCenter server, it must also be defined as a vCenter client. Then run the initial VM backups. The VM must be backed up once and can then be added to a Live Sync schedule.




To configure Live Sync

1 - Right-click the BackupSet or subclient | Live Sync | Configuration.

2 - Select the destination vCenter client

3 - Select the Proxy Client to execute the live sync.



4 - Click to add virtual machine to the replication .

5 - Select one or several VMs to configure.

6 - Define the destination VM name, the ESX server and datastore.

7 - Click to View or modify additional vCenter Options including resource pool, VM folder, Networking and IP settings.



8 - Select the disk provisioning method and the transport mode. View or modify additional settings including Validation, Unconditional Overwrite and Distribution of VM recovery workload



9 - Run the synchronization either after backups or on schedule.

10 - Give a name to the Live Sync schedule and choose the frequency of operation.

11 - On schedule or after the backups, a Replication schedule is initiated.


Live Sync from a Secondary Copy

Right-click the desired subclient or backup set | Live Sync | Configuration | Advanced | Copy Precedence tab

By default, Live Sync replicates from backups in the primary copy of a storage policy. It is possible to modify this behaviour to restore from a secondary copy. This can be useful when the VM is backed up to a disk library that is replicated to a remote site where the replicated machine resides.

When Live Sync is configured to use an auxiliary copy or backup copy, the Live Sync operation uses the copy as the source rather than the primary backup. If the 'After Backup Job Completes' option is selected in the schedule, Live Sync automatically waits until the data is ready on the secondary copy before running the Live Sync job.




To configure Live Sync from a secondary copy

1 - Right-click the desired backup set or subclient | Live Sync | Configuration.

2 - Click to reach advanced options.

3 - Check and define the precedence number.


Live Sync Monitor

Right-click the desired subclient or backup set | Live Sync | Monitor

The Live Sync Monitor tool is used to monitor and control live sync replication. In addition to the replication status of VMs, replication can be enabled/disabled and VM failover/failback can be initiated.




To open the Live Sync Monitor

1 - Right-click the desired backupset or subclient | Live Sync | Monitor.

2 - Replication status of each VM is displayed.



3 - Right-click a VM open tasks menu.

4 - Opens and allows to edit the Live Sync schedule.

5 - Disable or Enable a Live Sync schedule.

6 - Failover or Failback a VM.


Live Sync Failover

From the Live Sync Monitor | Right-click the desired VM | Failover

From the Live Sync Monitor, the failover of a virtual machine can be initiated. It can be defined as a planned failover, for testing purposes for instance, or unplanned, such as in a disaster situation. Once a VM was failed over, a failback operation can be executed. In a failback, the VM from the failover location gets backed up and synced back to the primary site.

Prerequisites to use failover feature:

  • The Workflow engine must be installed on the CommServe® server.
  • The 'allowToolsToExecuteOnServerOrClient' additional settings key with a value of seven (7) must be created on the CommServe server.
  • The VMs must have been synced at least once.

The Failover of a VM provides few options which are as follows:

  • Test Boot VM – Powers on the replicated VM. It is useful to test and ensure that it is useable in the case of a disaster. The destination VM is not modified to avoid any conflicts with the production VM.
  • Planned Failover – The planned failover is useful to test the complete failover scenario or to conduct maintenance on the primary site. A planned failover achieves the following tasks:
  1. Powers off the source VMs.
  2. Performs an incremental backup of the source VMs
  3. Runs Live Sync to synchronize the destination VMs with the latest changes
  4. Disables Live Sync
  5. Powers on the destination VMs with the appropriate network connections and IP addresses
  • Unplanned Failover – The unplanned failover is used in a real disaster scenario where the primary site is unavailable. In this scenario, the unplanned failover does not care about the primary site and achieves the following tasks:
  1. Disable Live Sync
  2. Powers on the destination VMs with the appropriate network connections and IP addresses




To initiate a failover

1 - From the Live Sync Monitor | Right-click the VM to failover | Failover.

2 - Choose to execute a test, planned or unplanned failover.

3 - Select the desired VMs.

4 - The failover job appears in the job controller.


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