Disk Image

Zmanda Pro offers different protected item types to cater to diverse backup needs. One such type is the "Disk Image," which allows you to capture the entire contents of a disk or specific partitions.

How it works:

  • When you select a drive or partition for a disk image backup, Zmanda Pro copies the entire contents directly.

  • This data is then compressed, deduplicated (meaning any duplicate data is stored only once), and encrypted for secure storage.

  • Zmanda Pro only backs up the used portions of the disk by default. Unused space is skipped to save storage space. You can choose to include unused space for specific reasons.

Things to Consider:

  • File exclusions are not possible within a partition being backed up with a disk image.

  • Fragmentation on the physical drive or a large number of small files can reduce deduplication effectiveness.

Operating system compatibility

Disk Image backup is available exclusively for Windows operating systems, including Windows 7, Windows Server 2008 R2, and newer versions.

Unused disk sectors

What is Unused Disk Space?

When you back up your data with Zmanda Pro, it's smart enough to skip over parts of your disk that aren't being used. This means it doesn't waste time and space storing empty areas. These empty areas are called "unused disk sectors." Zmanda Pro compresses these areas during the backup process to save even more space.

An option named "Include unused disk sectors for forensic data recovery" allows including unused sectors in backups, which might be necessary for forensic investigations. However, Zmanda Pro can only skip unused space on disks set to "Online" in Windows Disk Management. If it's set as "Offline," Zmanda Pro can't skip those empty spaces, even if it's a supported filesystem.

For partitions lacking a filesystem (like raw data areas), Zmanda Pro can't differentiate between used and unused space. So, if you choose to back up these raw areas, Zmanda Pro will save all of it, regardless of whether it's empty or not. If the raw data mostly contains zeros, it gets compressed really well during backup. But if it's random data, compression won't work as effectively.

Important Considerations:

  • Disk Online Status: Zmanda Pro can only skip unused space on disks set to "Online" in Windows Disk Management. You can change a disk's online/offline state using Disk Management (diskmgmt.msc) or the diskpart command-line tool.

  • Raw Partitions: Zmanda Pro cannot differentiate between used and unused space on partitions without a file system (e.g., raw partitions). These partitions are backed up entirely.

  • Pagefile Exclusion: Zmanda Pro always excludes the Windows pagefile (pagefile.sys or swapfile.sys) from backups, regardless of the unused sector settings.

  • Disabling Skipping Free Space: Zmanda Pro offers an option labeled "Include unused disk sectors for forensic data recovery." Enabling this option disables the skipping feature for unused sectors.

Drive letter support

Zmanda Pro allows selecting disks/partitions using their drive letter (e.g., C: drive).

We advise using the "Live Picker". However, drive letter selection can be useful for:

  • Creating backup policies.

  • Situations where a live connection to the device is unavailable.

Here's how drive letter selection works:

  • A drive letter with a single partition will back up the entire drive.

  • A drive letter with multiple partitions will only back up the partition associated with that specific drive letter.

To use this feature through Zmanda Pro web interface, change the Type value to "Include drive letter" when adding a Disk Image. If you're using Zmanda Pro desktop app, first turn on the option called "Select by Drive Letter (advanced)" on the Items tab, then switch to the Drive Letters tab to make your selections.

Supported volume types

When it comes to backing up your data with Zmanda Pro, it's important to know which types of filesystems and volume setups are supported.

Filesystem Support:

  • NTFS (Microsoft): Zmanda Pro can skip over unused space and ensures snapshot consistency.

  • ReFS (Microsoft): Similar to NTFS, ReFS is fully supported with skipping unused space and snapshot consistency.

  • FAT32 and exFAT (Microsoft): These filesystems are supported too, but skipping unused space only happens if the volume isn't in use.

  • UDF (Microsoft): This filesystem isn't fully supported for skipping unused space.

For other filesystems like WinBtrfs, Ext2Ifs, Paragon Linuxfs, and ZFSin, they haven't been officially tested with Zmanda Pro.

Special Volume Types:

  • Basic Disks: Standard hard drives and SSDs are fully supported by Zmanda Pro.

  • Dynamic Disks: These are configured using multiple physical disks. Zmanda Pro will recognize the underlying volume as a "Raw byte range." When backing up spanned or striped volumes, ensure you select only the dynamic volume itself, not the individual raw disks. It's important to note that Microsoft has deprecated Dynamic Disks in Windows 8 and later versions.

  • Storage Spaces: A feature in Windows that allows combining physical disks into virtual storage pools. Zmanda Pro will recognize these as "Orphaned volumes." Make sure to only select the Storage Space itself for backup.

  • BitLocker Drives: Zmanda Pro can back up unlocked BitLocker volumes. However, the resulting backup won't be encrypted. You can extract individual files without the BitLocker key. If restoring to the original partition, you might want to re-enable BitLocker after the process.

  • Cluster Shared Volumes & Encrypted Drives (TrueCrypt/VeraCrypt): These are not currently supported by Zmanda Pro.

Supported Physical Media:

  • Hard Drives (512n & AF): Both traditional 512-byte sector and newer Advanced Format (AF) hard drives are supported, including 512e and 4Kn sector sizes.

  • Mounted VHD/VHDX Disks: Virtual hard disks can be backed up if they are mounted as volumes in Windows.

  • Removable USB Drives: Backups of USB drives are possible. However, some removable drives might not be suitable for restore operations due to potential interference from other programs running on the system.

  • Remote iSCSI LUNs: Zmanda Pro has been successfully tested for backing up iSCSI LUNs presented by Windows Server File and Storage Services.

Unsupported Media:

  • Mounted ISO files, optical discs (CDs, DVDs, Blu-ray), floppy drives, and iSCSI LUNs from other operating systems are not supported for backup.

Partition Table Support:

  • Both MBR (Master Boot Record) and GPT (GUID Partition Table) partition tables are fully supported by Zmanda Pro.


Zmanda Pro tries its best to ensure your backups are consistent:

  • It attempts to take a VSS snapshot or lock the volume handle. If successful, the backup is considered crash-consistent.

  • If it can't do either, it'll still back up your data but warns about potential inconsistencies, especially if other processes are writing to the partition simultaneously.


When you need to restore data with Zmanda Pro, you have several options available. Zmanda Pro stores your data in a format called VMDK (Virtual Machine Disk). A VMDK file contains your backed-up data in a virtual disk format.

Components of a VMDK File

  1. VMDK Descriptor File: This file contains metadata about your entire disk, including information about each partition.

  2. Raw Image Files: These files store the actual data of each partition on your disk. Each partition has its own raw image file.

Recovery of single files, with spooling

Spooling refers to temporarily storing data before processing it. Here are some tools that enable spooling while recovering individual files:

  • 7-Zip (Free, Open Source - Windows/macOS/Linux): Opens VMDK descriptors and extent files, supports various filesystems (NTFS, FAT32, EXT2/3/4, UDF, HFS, SquashFS).

    • Known Issues:

      • Loading the VMDK descriptor directly might not show partitions if no partition table is present. Open the individual extent files instead.

      • Early versions have limited disk image feature support. Ensure you have the latest update (no built-in update feature).

  • DiskInternals Linux Reader (Freeware, Windows-only): Mounts VMDK files as a drive letter.

    • Known Issue: Fails to open the VMDK descriptor if "Raw byte range" areas contain junk data. Replace this with zero extents by editing the descriptor file (e.g., change RW 16065 FLAT "disk-f0000.vmdk" 0 to RW 16065 ZERO).

  • Passmark OSFMount (Freeware, Windows-only): Mounts VMDK extent files as a drive letter.

    • Known Issue: While it can discover disk partitions when loading the VMDK descriptor, mounting fails (both individual partitions and the entire VMDK as a raw disk). Workaround: Select individual extent files for mounting (works in "Logical Drive Emulation" mode).

  • ImDisk Virtual Disk Driver (Freeware, Windows-only): Mounts individual RAW extents and parses the VMDK descriptor to scan for discoverable volumes, allowing individual mounting.

  • VMware Workstation (Commercial software with free trial available - Windows/macOS/Linux): Offers a feature to mount VMDK files as a local drive letter (access through "File" menu -> "Map Virtual Disks"). Refer to VMware Documentation for more information.

  • Guestfs (Free, Open Source - Linux-only, command-line): Mounts the VMDK descriptor file using an unprivileged FUSE backend. Usage: guestmount -a disk.vmdk

  • Loop device (Free, Open Source - part of the Linux kernel, command-line): Mounts individual partition extents using the losetup tool (from util-linux).

Note: Ensure the VMDK descriptor file doesn't contain junk data in "Raw byte range" areas, as it might hinder mounting. Edit the descriptor file to replace such data with zeros if necessary.

Recovery of single files, without spooling

Refer to the Disk Image guide for details.

Booting into a recovered Windows OS installation

Here are some additional points to consider when recovering a Windows OS installation:

  • Licensing Issues: Moving a Windows OS installation to different hardware might trigger licensing issues with software that relies on hardware identifiers for activation.

  • Incomplete Backups: Recovering only the "C:" drive might not be enough to boot the OS successfully. Consider including the following in your backups for a complete recovery:

    • The disk's non-partitioned space (containing the GPT/MBR partition table).

    • "System Reserved Partition" (if present, holds the volume boot record).

    • On GPT disks and/or UEFI-booting devices, the EFI ESP partition may be presen

Windows 8.1, Windows 10, and Later:

  • These versions generally handle booting on dissimilar hardware without major issues.

Earlier Windows Versions:

  • Restoring a Windows OS image from a different machine might cause automatic hardware specialization, enhancing performance but potentially preventing a successful boot on very different hardware.

  • If you encounter booting problems, consider preparing the Windows installation for hardware independence:

    • Run the sysprep tool within the original Windows installation before creating the backup image.

    • Alternatively, boot into a Windows recovery environment, mount the restored image, and run sysprep on the attached disk.

  • Refer to official Microsoft documentation for detailed instructions on using sysprep (Sysprep (Generalize) a Windows installation ).

Filesystem smaller than target volume

  • When restoring a disk image with a smaller filesystem than the target volume, there are two approaches:

    • Expand the filesystem: Some tools (e.g., gparted for Linux) allow resizing the filesystem to utilize the entire target volume space.

    • Leave unused space unallocated: This approach is simpler but creates unallocated space on the target disk.

Expanding the Filesystem:

  • Ensure the tool you use is compatible with the target filesystem type (e.g., NTFS, EXT4).

  • Refer to the tool's documentation for specific instructions on expanding filesystems.

You can manually expand the filesystem to fill its containing partition on Windows by repeating Zmanda Pro's attempt separately by:

  1. As an administrator, launch Command Prompt.

  2. Execute the diskpart.exe command.

  3. To see a list of volumes, type list volume.

  4. Select volume X, where X is the target volume number, should be typed after you have chosen the desired volume from the list based on its size or drive letter.

  5. To start the extension process, type extend filesystem.

You can use the ntfsresize command on Linux to fix this problem.

Keep in mind that ntfsresize is only compatible with NTFS filesystems. To find utilities that work with other filesystem formats, such as resize2fs for EXT4, check the documentation included with your distribution.

Filesystem larger than target volume

Restoring huge partitions into smaller physical partitions is not supported by Zmanda Pro. Use the OS's partition manager to reduce the partition if needed before starting the backup.

Recovery to physical hardware

In order to restore data to physical hardware, follow these steps:


  • A physical machine with compatible hardware specifications for the recovered OS.

  • A bootable recovery environment (one of the following):

    • Windows Recovery Environment (WinRE) USB or ISO: Created using the Zmanda Pro desktop application (recommended).

    • Linux Bootable USB Drive: Created using a third-party tool like Rufus.

    • Recovery Media from your PC OEM Vendor (e.g., Dell, HP): These may require manual launching of Zmanda Pro after booting.

  • Unmount Target Disk: Ensure that the target disk or partition is unmounted to prevent conflicts during the restoration process. Zmanda Pro may automatically unmount the target drive if no programs are using it. For restoring to the boot drive, reboot the PC into a recovery environment.

Creating Recovery Media

Zmanda Pro supports creating recovery media from the desktop app. Here are the available options:

  • WinRE USB: This option creates a minimal USB Recovery Media based on the Windows Recovery Environment (WinRE). It requires a removable USB drive and supports both MBR and UEFI PCs.

  • WinRE ISO: Generate an ISO image file based on the Windows Recovery Environment. This option provides flexibility in deployment and booting on both MBR and UEFI PCs.

  • Windows To Go: Create a full Windows boot environment on an external hard drive of at least 32GB in size.

Recovering Using Zmanda Pro Recovery Environment:

  1. Launch the Zmanda Pro desktop application on your current system.

  2. Navigate to the "Account" screen and select "Recovery Media."

  3. Choose between creating a WinRE USB or ISO image:

    1. WinRE USB: Requires a removable USB drive with at least 2GB of free space. This option is recommended for ease of use.

    2. WinRE ISO: Creates an ISO image file that can be burned to a disc or used with virtualization software.

Booting into the Recovery Environment

  1. Connect the WinRE USB drive or boot from the disc/virtual drive containing the WinRE ISO.

  2. The Zmanda Pro desktop application will launch automatically.

Restoring Disks and Partitions

  1. Within Zmanda Pro, navigate to the "Restore" wizard.

  2. Select the desired backup from the backup repository.

  3. Choose the disk or partition you want to restore from the left-hand pane.

  4. Select the target disk or partition on the target physical machine from the right-hand pane.

    • Use the "Edit" button to repartition target drives using Windows Disk Management (if using WinRE).

    • Refresh the partition list after making modifications.

  5. Click "Add to Restore Queue" for each disk/partition you want to restore.

  6. Click "Restore" to begin the recovery process.

Restoring from a Linux Boot Environment

If using a Linux boot environment, the recovery process involves more manual steps using command-line tools. Refer to the Zmanda Pro documentation for detailed instructions on:

  • Restoring entire disks with/without spooling.

  • Restoring individual partitions with/without spooling.

Important Considerations

  • Ensure the target disk or partition is unmounted before initiating a restore. Zmanda Pro might be able to handle this automatically if restoring from a non-boot drive on Windows.

  • Booting the target machine after a full disk restore might require additional configuration depending on the OS and hardware compatibility.

  • Recovering a Windows OS installation to dissimilar hardware might cause licensing issues or require hardware-specific driver installation. Refer to Microsoft's documentation for details on preparing Windows installations for hardware independence (e.g., using Sysprep).

Recovery to local VM

Zmanda Pro backups utilize VMDK disk image files compatible with various virtualization platforms.

Attaching the VMDK Files

  1. Open your chosen virtualization platform's management console (e.g., VMware Workstation, VirtualBox).

  2. Set up a fresh virtual machine or pick an already existing one.

  3. Locate the "Add Hard Disk" option in the VM configuration menu.

  4. Choose "Existing Disk" and browse to the location of your Zmanda Pro VMDK files.

  5. Select the desired VMDK file(s) and confirm attachment.

Compatibility with Virtualization Platforms

Zmanda Pro's *.vmdk file format harmonizes effortlessly with various virtualization platforms:

  • VMware Fusion / Player / Workstation: Full compatibility ensured.

  • VMware vSphere: While direct support is absent, you can restore by treating it as a VMware virtual disk to generate compatible disk images.

  • QEMU: Smooth integration guaranteed.

  • VirtualBox: A perfect match.

  • Hyper-V: While direct support is missing, you can bridge the gap by converting to VHD or VHDX format.

Converting for VMware ESXi

For those aiming to restore as a VMware vSphere virtual machine, a conversion to ESXi-compatible format is necessary:

  1. Make the restored VMDK files accessible on your VMware Datastore.

  2. SSH into your ESXi server and navigate to the directory housing the restored VMDK files.

  3. Utilize vmkfstools to conduct the conversion.

  4. Configure the VM within ESXi as per your requirements.

Conversion for Hyper-V

To achieve compatibility with Hyper-V, convert the VMDK files to the VHDX format:

  1. Obtain qemu-img for Windows from the official source.

  2. Execute the qemu-img convert command to perform the conversion.

  3. Once done, remove the original VMDK files from the system.

Recovery to cloud server

If cloud recovery is your avenue, Zmanda Pro supports uploading *.vmdk disk image files to multiple cloud providers:

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