Windows image-level protection employs block acceleration to deliver lightning-fast backup performance for Windows servers, particularly those with millions of files. Because Windows assets are backed up at the disk and volume level, image-level protection yields faster backup performance than file-level protection. With this increased backup speed, you can snapshot more frequently to reduce data loss in the event of an outage.
See these topics to get started with image-level protection:
Features of image-level and file-level protection are given here:
Feature |
Image-level backup |
File-level backup |
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Data protected |
The following apply to image-level protection:
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The following apply to file-level protection:
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Backup options |
Image-level backups support these options:
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File-level backups support these options:
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Backup and recovery job performance |
Image-level jobs yield faster backup and recovery:
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File-level jobs yield slower backup and recovery:
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Backup size |
Image-level full backups may be larger than file-level fulls of the same asset. Smaller deduplication ratio than with file-level backups. (Fewer duplicate blocks found, more unique blocks stored.) This may result in decreased on-appliance retention. |
File-level full backups may be smaller than image-level fulls of the same asset. Greater deduplication ratio than with image-level backups. (More duplicate blocks found, fewer unique blocks stored.) This may result in greater on-appliance retention. |
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Recovery |
These recovery procedures are supported for image-level backups:
For details, see Recovering Windows Image-level Backups. |
These recovery procedures are supported for file-level backups:
For details, see Recovering File-level Backups. |
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Hosted applications |
Image-level backups are taken with VSS copy-only snapshots. Full image-level backups do not truncate application logs. Run Unitrends application backups along with image-level backups to protect hosted applications. (See Application backups below for details.) |
File-level backups are taken with VSS full snapshots. Full file-level backups do not truncate application logs. Active Exchange databases and active SQL user databases are automatically excluded from backup. SQL system databases are always included to support Windows replicas. Run Unitrends application backups along with file-level backups to protect hosted applications. (See Application backups below for details.) |
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Unitrends application backups provide these benefits:
For more on application protection, see Application Backups Overview. |
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SLA policies |
SLA policies supported for image-level backups. |
SLA policies are supported for file-level backups. |
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Copy Data Management |
Image-level backups can be used with the Copy Data Management feature. |
File-level backups can be used to create Windows replicas. Windows replicas that reside on a VMware or Hyper-V host can be used with the Copy Data Management feature. |
Follow these best practices to protect your Windows assets with image-level backups:
• | Adhere to Microsoft best practices. |
• | Full and incremental backups are supported for image-level backups. |
• | A new full backup is required if the disk or volume configuration has changed since the last backup. This includes any change to the number, size, or properties of the disks or to the number, size, or properties of the volumes on a disk. |
If the disk or volume configuration has changed since the last backup, the appliance promotes the next scheduled backup to a full (or displays a message indicating a full is required if an on-demand incremental is attempted). Once a full backup succeeds, subsequent incrementals run as scheduled.
• | A new full backup is required if the disk or volume configuration has changed since the last backup. This includes any change to the number, size, or properties of the disks or to the number, size, or properties of the volumes on a disk. |
If the disk or volume configuration has changed since the last backup, the appliance promotes the next scheduled backup to a full (or displays a message indicating a full is required if an on-demand incremental is attempted). Once a full backup succeeds, subsequent incrementals run as scheduled.
Note: Protecting a given image-level asset by using more than one appliance is not recommended. Each time a backup is run on an one appliance, the integrity of the incremental backup chain on any other appliance is compromised. To correct a compromised backup chain, the appliance automatically promotes the next incremental to a full. Because of this, running incrementals on multiple machines is likely to result in many full backups.
The following requirements must be met for image-level protection of Windows assets:
Item |
Description |
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Unitrends appliance |
These requirements apply to the Unitrends backup appliance:
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Windows agent |
The Windows asset must be running Unitrends agent version 10.3 or higher with the Volume CBT driver. During agent installation, you have the option to install the Volume CBT driver. The Volume CBT driver is needed to run image-level incremental backups. After you install the Windows agent and Volume CBT driver, you must reboot the Windows asset to enable the driver. For details, see Installing the Windows agent. Notes:
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Windows asset |
See these rows below for Windows requirements: Note: Additional Windows requirements apply for instant recovery. For details, see Windows asset requirements for IR.
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The operating systems listed below are supported. (Additional version limitations apply. See the Compatibility and Interoperability Matrix for details.) Supported client operating systems:
Supported server operating systems:
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Image-level protection is supported for BIOS- and UEFI-based assets.
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Image-level protection is supported for Windows machines configured with basic disks only. Dynamic disks are not supported. Offline disks are included in image-level backups. |
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Image-level protection is supported for GUID Partition Table (GPT) partitions and Master Boot Record (MBR) partitions. |
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Image-level protection is supported for these file systems: NTFS, FAT, FAT32, exFAT, and ReFS. Note: Due to a Microsoft limitation, VSS snapshots cannot be taken of these volumes: FAT, FAT32, and exFAT. Backups of these volumes may contain data that is not in a consistent state if data changes during the backup job. |
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Image-level protection is not supported for read-only disks. You must exclude all volumes on read-only disks from the backup job or run file-level backups. Image-level backups fail if read-only volumes have not been excluded. (For details on excluding volumes, see step 4 in To create an image-level backup job.) Note: Removable media is automatically excluded from image-level backups. You do not need to exclude volumes on a read-only disk that resides on removable media. Image-level protection is not supported for VHD or VHDX files that are mounted as local volumes. For details, see VHD or VHDX files that are mounted as local volumes. |
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Image-level protection is not supported for the following features. Use file-level protection instead:
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Image-level protection is not supported for VHD or VHDX files that are mounted as local volumes.
If you include one of these locally mounted volumes in an image-level backup, recovery from the backup yields undesired results.
Protecting unmounted VHD or VHDX files is supported. For example:
Protecting a volume that was created by mounting a local VHD(X) file is not supported. For example: