Image-level replica requirements

The following topics cover the requirements for image-level replicas:

NOTES   

●   Only one Windows replica can exist per Windows asset. You cannot run both an image-level replica and a file-level replica of the same asset at the same time. If a replica exists, you must tear it down before creating another for the asset.

●   You can opt to run image-level replicas in the Unitrends Cloud. Contact your Account Manager for assistance.

An image-level backup of the physical Windows machine is required to create the replica. (To use a Windows file-level backup, see Windows file-level replicas.)

●   The backup must contain all boot and critical system volumes.

●   The backup must be a local backup run by the appliance where you are creating the Windows replica or a hot backup copy run on the backup copy target appliance. You cannot create a replica from an imported backup.

NOTES   

●   By default, image-level backups include all system information needed for replicas. If you opt to exclude volumes from backup, use care not to exclude the boot and critical system (OS) volumes.

●    The replica virtual machine is created based on the backup you select. Volumes that were excluded from backup are not recovered.

●   If the image-level backup includes SQL or Exchange, the replica automatically includes these applications. For details on how these applications are handled by image-level backups, see Hosted applications.

●   For SQL, the master, model, and msdb system databases must also be present in the image-level backup of the Windows asset. (These are included by default. If you want the replica to include a hosted SQL application, use care not to exclude these system databases from the image-level backup.)

Back up the Windows asset regularly to keep the replica up to date. See these topics for details:

●   To create a job manually, see To create an image-level backup job.

●   To create a job by using an SLA policy, see To create an SLA policy for Windows image-level assets.

●   For a comparison of the manual and SLA policy job creation methods, see About creating backup and backup copy jobs.

Requirements vary by where the replica resides. See these topics for details:

The replica can reside on any of the following: a Recovery Series physical appliance, a Recovery MAX physical appliance, an ESXi server, or a Hyper-V server. Considerations for each are given in the following table.

Replica location

Considerations

Recovery Series or Recovery MAX physical appliance

Running the replica on the backup appliance itself provides a simple, seamless solution. Note that only Recovery Series and Recovery MAX physical appliances have this option. (A replica cannot reside on a Unitrends Backup virtual appliance.) Consider the following to determine whether this is the optimal replica location for your environment:

●   Requires no additional hardware. Provides near-zero RTO without having to increase CapEx.

●   Assumes the role of a failed Windows server temporarily, until you can get new hardware and run a bare-metal recovery.

●   Provides seamless, continuous protection in a failover scenario. The 'live' replica is automatically protected by the existing backup schedule after assuming the identity of the original Windows machine.

●    Uses the compute resources of the appliance to bring the replica 'live' in a failover scenario. If the appliance is already under high load, there may not be sufficient resources to provide for replicas.

●   Reduces on-appliance backup retention because a portion of the appliance’s storage is reserved for the replica.

ESXi or Hyper-V server

Running the replica on an ESXi or Hyper-V server enables access to the compute and storage in your virtual environment, greatly increasing the pool of resources that can be used for replicas. Consider the following to determine whether this is the optimal replica location for your environment:

●   Leverages virtual infrastructure for replicas. Disk space and compute resources of the Unitrends appliance are not impacted.

●   Provides the ability to dynamically scale compute resources in the virtual infrastructure during failover, enabling 'live' replica performance to match that of the original Windows asset.

●   Provides the option to use the replica VM as a permanent replacement for the failed Windows asset. Can be used to migrate a physical Windows machine to your virtual infrastructure.

Ensure that the following requirements have been met before you create the image-level replica.

Requirement

Description

Appliance and agent version

The Unitrends appliance where the replica will reside must be running version 10.5.3 or later. The Windows asset must be running agent version 10.5.3 or later.

Allocate storage

Appliance storage can be used to store backups, for VM instant recovery, or for Windows replicas. To use the Windows replica and VM instant recovery features, you must allocate a portion of the appliance storage to Instant Recovery in the Edit Storage dialog (as described below).

Before allocating storage, determine the percentage to use for backups and the percentage to reserve for Windows replicas and VM instant recovery.

Once storage is allocated to instant recovery, it can be used only for Windows replicas and VM instant recovery. The storage is reserved and cannot be used for other purposes, such as backups or deduplication (but you can modify your storage allocation at any time).

Because the appliance is designed to retain as many local backups as possible, it is best to reserve instant recovery space soon after initial deployment. If necessary, you can allocate instant recovery space later, but doing so may require the appliance to purge local backups to make room for the newly allocated instant recovery space.

NOTE  You do not need to allocate instant recovery storage if the Windows replica will reside on an ESXi or Hyper-V server. This procedure is only required for Windows replicas that reside on the appliance itself.

1.  On the Configure > Appliances page, select the appliance, then click the Storage tab below.

2.  Select the Internal storage and click Edit.

3.  Modify the storage percentages allocated to Backups versus Instant Recovery (IR).

The minimum IR space needed for a replica is the total amount of space in use on the original asset (the sum of used space on all disks).

4.  Click Save.

Unitrends appliance resources

The replica uses part of the Unitrends appliance’s processors, memory, and storage. This usage may impact the performance of regular system functions (such as backups, backup copies, deduplication, and purging). Monitor the appliance closely and make adjustments as necessary.

Minimum replica requirements:

●   One replica requires a minimum of 2048 MB of memory.

●   One replica requires a minimum of 1 core processor when in an idle state.

UEFI-based assets

Windows replicas of UEFI-based assets are supported on the following:

●   ESXi servers

●   Hyper-V servers

●   Recovery Series appliances running the CentOS 7 operating system

●   Recovery MAX appliances running the CentOS 7 operating system

Windows replicas of UEFI-based assets are NOT supported on physical appliances running the CentOS 6 operating system.

To check the appliance OS version, select ? > About in the appliance UI:

GPT-partitioned assets

Instant recovery is supported for GPT-partitioned volumes.

Ensure that the following requirements have been met before you create the image-level replica.

Requirement

Description

Hypervisor version

The ESXi host must meet these requirements:

●   Must be running ESXi 5.1 or a higher version listed in the Compatibility and Interoperability Matrix.

●   Must support the operating system (OS) of the Windows asset. (See the VMware documentation for details.) For example, a replica of a Windows 2016 asset cannot reside on an ESXi 5.1 host.

Virtual host asset

The ESXi server must be added to the appliance as an asset. See Adding a virtual host.

Compute

One replica requires a minimum of 2048 MB of memory. (This number must be a multiple of 4.)

Replica VM changeability

Once you have configured the replica in the Create Windows Replica dialog, do not make any changes to the replica VM. Any alteration to the replica (unless it is in live mode) may lead the replica to an inconsistent state.

Maximum disk size

The maximum disk size is capped by what the hypervisor supports. The replica's disks will be the same size as those on the original asset. For Windows assets with disks larger than 2 TB, the ESXi server must be running ESXi 5.5 or a higher version listed in the Compatibility and Interoperability Matrix.

Virtual hardware version

The replica VM is configured with the highest hardware version that the hypervisor supports.

Ensure that the following requirements have been met before you create the image-level replica.

Requirement

Description

Hypervisor version

The hypervisor must be one of the following:

●   A Windows Server with the Hyper-V role enabled, running 2008 R2 or a higher version listed in the Compatibility and Interoperability Matrix.

●   A Hyper-V Server running 2008 R2 or a higher version listed in the Compatibility and Interoperability Matrix.

The Hyper-V host must support the operating system (OS) of the Windows asset. (See this Microsoft article for details: Should I create a generation 1 or 2 virtual machine in Hyper-V?) For example, a replica of a Windows 2016 asset cannot reside on a Hyper-V 2008 R2 host.

Host agent version

The Hyper-V host must be running Unitrends agent version 10.5.1 or higher.

It is best practice to run the latest Unitrends appliance and agent software versions. Older versions do not support all current Unitrends features.

Virtual host asset

The Hyper-V host must be added to the Unitrends backup appliance as a protected asset. See Adding a virtual host.

Virtual host Samba access

The Hyper-V server must be able to access the appliance's Samba share:

●   SMB 2.0 – The SMB 2.0 security option is enabled by default on Unitrends appliances that were originally imaged or deployed with version 10.4.8 or higher. SMB 2.0 must be enabled on the Hyper-V server.

●    SMB 1.0 – The SMB 1.0 security option is enabled by default on appliances that were originally imaged or deployed with a pre-10.4.8 version. SMB 1.0 must be enabled on the Hyper-V server.

NOTE   Upgrading from a pre-10.4.8 version does not change the SMB 1.0 setting. (To configure your appliance to use SMB 2.0, see How Unitrends supports SMBv2.)

Compute

One replica requires a minimum of 2048 MB of memory. (This number must be a multiple of 4).

Replica VM changeability

Once you have configured the replica in the Create Windows Replica dialog, do not make any changes to the replica VM. Any alteration to the replica (unless it is in live mode) may lead the replica to an inconsistent state.

Maximum disk size

The maximum disk size is capped by what the hypervisor supports. The replica's disks will be the same size as those on the original asset. For Windows assets with disks larger than 2 TB, the Hyper-V server must be running version 2012 or a higher version listed in the Compatibility and Interoperability Matrix.

Replica VM configuration

The replica VM is created with this configuration:

●   The asset's firmware interface type determines the generation of the replica VM. BIOS-based assets are created as generation 1 VMs, and UEFI-based assets are created as generation 2 VMs. A replica for a UEFI-based asset cannot run on 2008 R2.

●   The VM's configuration version is the highest version that the hypervisor supports.

Pass-through disks

Pass-through disks are supported.

After you bring the replica online to assume the role of the failed asset, you must refresh and reconnect any existing iSCSI targets.

Ensure that the following requirements have been met before you create the image-level replica.

Requirement

Description

Cluster asset

To run a replica on a Hyper-V server in a cluster configuration, ensure that these requirements have been met:

●   The Unitrends Windows agent is installed on each node in the cluster.

●   Every node in the cluster is running the same agent version.

●   Each cluster node and the cluster itself has been added to the appliance as an asset. (For details, see Working with Hyper-V servers.)

Storage

The Hyper-V cluster must be configured with Cluster Shared Volumes (CSVs). SMB storage is not supported.

PowerShell FailoverClusters modules

These modules must be installed on every node in the cluster so that the appliance can discover the CSVs.

Selecting the replica location

To create a clustered replica, you must select the cluster itself as the Location in the Create Windows Replica dialog. Do not select an owner node. If you select an individual node in the cluster, the replica will not be clustered.

Network switch selection

For a clustered replica, select the Network Switch common to all nodes in the cluster (in the Create Windows Replica dialog). If you do not select this switch, a 'live' replica that fails over to another node will lose network connectivity.

2008 R2 clusters

To run the replica on 2008 R2 servers in a cluster configuration, enable DCOM and WMI Virtualization access for all nodes in the cluster. For instructions, see Security settings for creating a clustered virtual failover client on Hyper-V server 2008 R2.

Live migration interoperability

During live migration of a clustered replica, the Unitrends appliance cannot apply backups to the replica, verify or audit the replica, or bring the replica online in production to assume the role of the original asset. If the appliance attempts to apply a backup or verify the replica during a live migration, the appliance waits several minutes and then attempts the operation again. If you try to audit the replica or bring it online in production, the appliance notifies you that it cannot run the operation because of the migration and you must try again later.

The Windows asset must meet the following requirements to use the image-level replica feature:

Requirement

Description

Operating System

The Windows OS must meet these requirements:

●   If running the replica on a virtual host, the Hyper-V or ESXi host must support the guest OS of the replica VM. (See the Microsoft or VMware documentation for details.) For example, a replica running Windows 10 cannot reside on ESXi 5.1 or Hyper-V 2008 R2.

●   For Windows 8.1 and Windows 2012 R2, the replica includes the data from all disks, but if created as a Gen 1 VM, only the first four disks are eligible as boot devices.

●   For Windows 2008 R2 SP1, these additional requirements apply:

●   These Windows security updates must be installed: Update for Windows Server 2008 R2 x64 Edition (KB2533623) and Security Update for Windows 7 for x64-based Systems (KB3033929). (If these updates have not been installed, you are prompted to install them during agent installation.)

●   The Unitrends Volume CBT driver (used to run image-level incremental backups) cannot be installed along with the Unitrends Windows agent. You must install it manually. During agent installation the Volume CBT installer is placed here: C:\PCBP\Installers\uvcbt.msi. To install the driver, simply run uvcbt.msi. After installing the driver, you must enable it by rebooting the Windows asset.

Applications

Some Windows applications require network access and/or rely on underlying hardware, like network interface MAC addresses, in order to run properly. When booting a replica in audit mode, there is no network interface, so applications requiring network connectivity will not function properly. This is expected behavior. When booting a replica in live or audit mode, applications that rely on unchanging hardware (like MAC addresses) may not function properly or may require re-authentication, re-installation, or other special actions that are application specific in order for them to work properly. You should work with the application vendor to determine what actions are required.

Firmware interface type

The replica feature supports BIOS- and UEFI-based assets.

For UEFI-based assets, the replica must reside on one of the following:

●   An ESXi server running ESXi 5.1 or a higher version listed in the Compatibility and Interoperability Matrix.

●   A Hyper-V server running 2012 R2 or a higher version listed in the Compatibility and Interoperability Matrix. For a replica running on Hyper-V, the UEFI-based asset’s OS must be 64-bit and running Windows 8 or higher.

●   A Recovery Series or Recovery MAX appliance that is running the CentOS 7 operating system.

NOTE  A UEFI-based replica cannot reside on a physical appliance that is running the CentOS 6 operating system.

Disk partition type

The replica feature is supported for assets with GUID Partition Table (GPT) and Master Boot Record (MBR) partitions.

For assets with GPT partitions, the replica must reside on one of the following:

●   An ESXi server

●   A Hyper-V server

●   A Recovery Series or Recovery MAX physical appliance that is running the CentOS 7 operating system. To check the appliance OS version, simply click on ? > About:

Software RAID volumes

The Windows image-level replica feature is not supported for software RAID configurations.

Deduplicated volumes

Volumes that use Microsoft deduplication are not supported in cases where the size of the data on the volume before it has been deduplicated is greater than the physical capacity of the volume. Because data is applied to the replica in its non-deduplicated form, the volume must have enough capacity to house this non-deduplicated data.

Number of volumes

The Windows asset can have a maximum of 20 volumes, including the System Reserved volume and other unmounted volumes. A replica with more than 20 volumes may fail to boot.

Separate boot and system partitions

For Windows assets with boot and system partitions located on different disks, the system partition must reside on the first disk (Disk 0).

File System Configuration

The replicas feature supports the following file systems:

●   NTFS

●   FAT/FAT32

●   ReFS (Windows 2012 and later)

Active Directory

The replica feature supports Active Directory database (NTDS) located on the boot volume only. (If it is not on the boot volume, the configuration is not supported and you see an error message when you attempt to create the replica.)