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Bare Metal Backup and Recovery: Definition and Types

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Updated 18th February 2024, Rob Morrison

Bare metal backup and recovery is typically one of the most critical elements of an enterprise’s backup and recovery strategy (often referred to as “disaster recovery strategy” or “DR strategy”).  There are a lot of different solutions available, each with its own individual advantages.

What is bare metal backup?

Bare metal backup is a process of backing up your entire system’s data, and it’s not just user data and settings – the entire system, including drivers, programs, information structure, and even the OS itself.

The term itself comes from a straightforward logic. A machine without OS or any other data can be referred to as “metal” – a hardware combination that the server or computer consists of. As such, restoring a backup image to one such hardware unit is “bare metal restore”, and creating a backup image for that same process is “bare metal backup”.

There are many advantages of such a method – that’s why currently more traditional file backup solutions are being slowly replaced with newer types of solutions, like bare metal backup. This method is becoming increasingly popular as time passes since a bare metal backup copies all of the data – customer files, settings, and even the OS itself.

There are instances where using regular file-based backup is easier and more convenient. However, there are also situations where the data on a machine or server is irreparable or entirely deleted (the most prominent example of this being the result of a natural disaster, such as flooding or burning). Solving these kinds of issues with bare metal backups is a lot easier than going through the entire process of setting up an OS, fine-tuning it for a specific purpose, and only then restoring the backup files.

What is a bare metal recovery (or bare metal restore)?

The other half of this solution type is bare metal restore or bare metal recovery. This one implies the process of recovering all of the backed-up data to completely new “bare” hardware, with all the settings, drivers, and other things like OS completely intact.

It follows the exact same logic as bare metal backup, but in ‘reverse’, so to speak – restoring a specific backup to a completely blank server or workstation. It is an advantageous option for larger companies in situations such as ransomware attacks, data breaches, and natural disasters.

The Advantages of bare metal backup and recovery

Some of the most significant advantages of this backup and recovery type are:

  • Speed. Bare metal recovery can be comparatively fast – since there’s no requirement to restore a particular piece of data, and the process is actually restoring everything, from drivers and registry to desktop icon layout, with no need to install all the drivers and programs from scratch. Bare Metal Restore may be performed on hardware other than the original.
  • Convenience. There’s no need to spend time setting up a new computer with all of the software you’ll need; instead, you can just use bare metal recovery and restore everything with a straightforward operation.
  • Safety and security. If your system is infected with something (virus, ransomware, etc), using bare metal restore should allow you to get rid of everything that could’ve caused that infection to begin with, including infected files, backdoors, and other potential threats to your system.

The Disadvantages of bare metal backup and recovery

Alternatively, there are also multiple shortcomings that bare metal backups have, including:

  • Hardware compatibility. The most significant drawback of this backup and restore solution is the need to have the same hardware configuration on the system from which the backup is taken and the “bare metal” system that’ll be recovered from said backup.

Regarding system hardware in the context of bare metal recovery, there are two main groups of hardware parts: boot-critical devices and other devices.

Some parts of the system can be different when performing a bare metal restore, like a sound card, a capture card, or a graphic card since they are not part of the boot process, and the system can load itself without them (even if with some problems). This “group” implies that, if necessary, you can install drivers for such devices after a bare metal restore process is complete and the system is up and running.

Boot-critical devices are an entirely different thing. Hardware parts like CPU, HDD controller, or motherboard need to be the same for both systems in order for the drivers to match and for the system itself to boot correctly. The inability to match those parts would not allow the system to boot.

  • Backup and restore rigidity. Due to the nature of a bare metal backup, restoring this backup usually offers little to no customization. The system in question is backed up in a specific state, and that entire state is restored as a result. As such, choosing what settings or applications to restore is not possible.
  • Sizeable downtime. Most of the bare metal backups are relatively large since they are just a tiny step away from a traditional “full” backup – the most space-inefficient backup type by far. The total recovery time from a bare metal backup may take a long time if a company’s network or infrastructure does not support high bandwidth (primarily if the recovery process is performed from a network backup storage).

Bare metal recovery use cases

There is a surprisingly large variety of different scenarios and use cases that bare metal recovery is used in, such as:

  • The transition from one server type to another (from virtual to physical servers and vice versa)
  • A case of operating system corruption created by the influence of an infected application
  • The aftermath of a ransomware attack, in most situations
  • The server hardware upgrade/replacement
  • An incorrect software upgrade that resulted in data corruption/deletion
  • A stolen or misplaced personal PC (laptop)
  • A system crash or an HDD failure

Bare Metal Recovery can also be used to create the same configuration on multiple different hardware appliances using so-called “master images” as the baseline.

The importance of bare metal recovery in the context of disaster recovery is exceptionally high. Bare metal recovery is a necessary part of most disaster recovery strategies since most restoration processes for image-based backups are performed using BMR as a baseline.

There is also the fact that detailed disaster recovery (as well as BMR, by association) is now considered a part of the well-known 3-2-1 rule. This rule initially provided the basic structure of a backup plan for end users to customize for their own needs. However, as the technology evolved over the years, more and more strategies and tactics were added to backup plan recommendations – including BMR capabilities.

What is included in a standard bare metal backup?

To expand upon the previously mentioned topic, a bare metal backup must include the following data categories:

  • System State.
    • A specific category of data that may be necessary for some of the backups to operate correctly; includes the sysvol folder, as well as NTDS, boot files, system registry, and COM+ class registration database.
  • System Volume.
    • A specific volume that contains the Operating System data.
  • UEFI or other partitions.
    • These system-related partitions usually contain critical data, including the Windows boot loader.
  • Installed applications or services.
    • Specific volumes representing currently installed applications and services. The importance of this category grows even more if these services or applications are not on the same drive as the OS.

How to execute Windows BMR with Bacula?

Bacula Enterprise performs bare metal recovery with additional, powerful options. To understand this, first, we would split this into two segments – explaining different processes performed on Windows and Linux machines.

It is worth mentioning that Bacula Enterprise offers many advantages to both Linux and Windows users regarding BMR operations. Some of the more prominent Windows-centric BMR advantages of Bacula include:

  • GPT table support.
  • UEFI and secure boot support.
  • Dynamic disk support.
  • Manual partitioning support.
  • Easy access to logs.
  • Extra ISO customization tools.
  • Support for three different backup types (full, incremental, differential).

The process of performing bare metal recovery on Windows systems can be roughly split into two large parts – the preparation/installation part and the restoration part. The former goes over the initial configuration of the process, including setting up the WinBMR backup software, creating backups, and so on. The latter starts with rebooting the system with the recovery device attached to it and goes through every step of the Bacula Windows Bare Metal Recovery wizard, from start to finish.

Initial setup and backup image creation

The first step in this entire process is to download specific files that are necessary for Bare Metal Recovery to be performed in the first place. There are three main files that we are looking for:

  1. bacula-enterprise-winXXWinbmrPlugin-X.X.X.exe – an installation file that contains the Bacula plugin the user would have to install on every single Windows system that needs to be protected using Windows BMR.
  2. winbmr-rescue-3.X.iso – the ISO disk image that would be used to boot the system for the subsequent recovery process, it can also be customized using the next file.
  3. winbmr-iso-configurator.exe – the aforementioned configuration executable file that can be used to modify the ISO’s initial settings, such as passwords, names, ports, and so on.

It is worth noting that the configurator file is not the only way to modify the values of the ISO file, because there are also several command-line arguments that could be used to do the same, such as:

winbmr-iso-configurator.exe –no-gui –iso winbmr-rescue-3.0.iso –cli-name=rescue-fd –cli-pass=xxx –cli-port=9102 –cons-pass=xxx –dir-address= –dir-name=bacula-dir.lan –dir-port=9101

Regarding the WinBMR plugin, it needs to be installed and launched to be able to create backups to begin with. During the backup process, this particular plugin analyzes both partitions and host disks to locate information that would be necessary for the restoration process. This data is then saved in a directory such as C:/Bacula/winbmr which saves partition data (including the EFI partition), disk layout data, and more.

WinBMR adds all static volumes to the set of files to be backed up during the restoration process, although it is possible to exclude some of the drives from being backed up or restored. Once you’ve created the backup of existing data and saved it to your ISO file, now it is time to begin the recovery process.

Restoring a bare metal backup from the recovery media

The restoration process is mostly performed using either the CD-ROM or the ISO image itself. The bare metal recovery process for physical servers recommends using CD-ROM as the recovery option, and the ISO image is recommended for virtual servers. While there is an option to create a bootable USB drive using the ISO image, it does not change the recovery process itself and thus we are going to proceed with the aforementioned two recommended options.

bacula windows bare metal recovery screen #1

Most of the restoration process is performed using Bacula’s Bare Metal Recovery wizard which has a helpful GUI to make the entire process easier for people of different skill levels. However, the first part of the bare metal restore process would be to boot the system using the Recovery Media: the ISO file or the CD-ROM. Most systems have the option to choose the primary boot device using their BIOS settings, although the proper key combinations necessary to load into BIOS may differ from one hardware provider to another.

While this approach does require either remote or physical access to the device in question, Bacula recommends it as the correct way to perform bare metal recovery for security reasons. Once you have managed to boot the system using Bacula’s Recovery Media, it starts with a minimal Windows setup that helps you configure your network settings, and then the Bacula Systems splash screen should appear before you.

A large part of the recovery process from now on is going to be performed using a number of different GUI-based choices and preferences in the following order:

  1. Choosing the preferred keyboard layout, leading to the program in question restarting (to accommodate your keyboard layout preferences from now on).
    bacula windows bare metal recovery screen #2
  2. Setting up a static IP address for this system if the network it works in does not have a DHCP server set up already – this is technically an optional step, but it is highly recommended to perform for everyone to avoid unnecessary problems in the future. The static IP settings menu can be found by clicking File -> Tools -> Network tab.
    bacula windows bare metal recovery screen #3
  3. The next screen lets you either modify the existing Bacula configuration that was loaded from the Recovery Media or proceed without any modifications to that same configuration. You would see the error message appear at this step if the Director was not able to connect to the recovery file daemon, or if the host was not able to connect to the Director – the error message must show the reason for the error, it can be helpful with figuring out what needs fixing.
    bacula windows bare metal recovery screen #4
  4. Once all of the problems have been resolved, you should be able to go to the next screen. At this point, Bacula’s wizard would show all of the clients that it was able to locate so that the user can choose which client needs to be recovered.
    bacula windows bare metal recovery screen #5
  5. Once a specific client has been chosen, the next window should show a list of the most recent backups performed for this client – a successful backup operation would have the letter [F] as the primary indication of its success. At this screen the user would have to choose both the backup job that would be used for the restoration process, as well as the restore job template – this setting can be modified, but the standard option should work in most cases with no issues.
    bacula windows bare metal recovery screen #6
    The following portion of the bare metal restore procedure may seem excessively complicated, but it is necessary to mention that the standard options for these tasks work in most common cases, meaning that the user in question would not have to have a deep understanding of the topic to be able to restore their system from scratch. Knowing that, it is time to move on with partitioning and choosing what volumes would be restored.
  6. The next screen showcases disks and partitions – including the ones that are currently operational, the ones that were recorded during the backup process, as well as the ability to choose which objects (volumes that have a letter assigned to them) to include in the recovery process or exclude them from that process. The main goal of this particular screen is to match the number of disks and the size of both the source host and the backup data. It is also possible to exclude some of the disks from this process (and it would also make every volume that is associated with it glow red to the right of these lists) or even restore data from one volume to another location, but these processes can only be performed by experts that know what they are doing.bacula windows bare metal recovery screen #7
  7. Another screen called “Manual Partitioning” only appears when the option with the same name is chosen at the previous screen – it allows users to be much more flexible with partitioning by saving all of their previous decisions to diskpart.txt with the ability to edit it if necessary. Assigning drive letters and creating/formatting volumes is a must for the user to pass this particular screen and proceed with the bare metal restore process.
    bacula windows bare metal recovery screen #8
  8. Volume matching is another sophisticated part of this process on another Bacula Bare Metal Recovery wizard’s screen. It allows users to tell the setup wizard the exact restoration location for every single volume pulled from the backup location. The software is capable of matching volumes with identical drive letters, which is why modifying this is only recommended when the user is not happy with the default settings.
    bacula windows bare metal recovery screen #9
  9. At last, the next screen would be the one where the user would be able to see the progress of the restoration process – with both the remaining time and the elapsed time being shown, as well as the general status information about the process.
    bacula windows bare metal recovery screen #10
  10. The last screen in the bare metal recovery process by Bacula showcases a detailed log of the recovery process, including detailed timestamps and possible error messages during and after the recovery was completed.
    final bacula windows bare metal recovery screen

How to execute Linux BMR with Bacula?

While Bacula does have a number of advantages that are only applicable to Windows users, there is also a group of benefits that are applicable to both Windows and Linux devices, including:

  • Bootable ISO creation.
  • Cloning capabilities.
  • Restoration to an entirely different type of storage (physical-to-virtual and vice versa).
  • User-friendly GUI.
  • Exceptional recovery performance.

The actual restoration process in terms of bare metal recovery for Linux has a lot of similarities to the way it is done in Windows, but the initial setup is several times longer – even though the logic behind it is also similar.

First of all, the Linux BMR system needs a direct contact with Bacula’s Director during the bare metal recovery process in order to be able to restore all of the data properly. As such, a Console resource needs to be set up beforehand via configuring the Director – using a procedure such as the one shown below.

Console {

Name = rescue-fd # same name as on your Client resource
Password = bacularescue
CommandACL = *all*
ClientACL = *all*
CatalogACL = *all*
JobACL = *all*
StorageACL = *all*
ScheduleACL = *all*
PoolACL = *all*
FileSetACL = *all*
WhereACL = *all*
# The next two ACLs are required when using
# Bacula Enterprise 8.8.0 and above
UserIdACL = *all*
DirectoryACL = *all*
# This last ACL is available when using
# Bacula Enterprise 8.8.0 and above but is not required
RestoreClientACL = *all*


Another resource that the system needs in order to perform bare metal recovery operations is Rescue Client – the example of its configuration is also shown below.

Client {

Name = rescue-fd # Use your rescue client nam
Address = # Will be set automatically by LinuxBMR
Password = bacularescue # USE YOUR OWN PASSWORD
Catalog = MyCatalog


The last resource that would be necessary for proper restore operation is a Job resource with the same name that does not have any specific RunScript directives. All three of these jobs are required for any data to be backed up for further restoration.

The next general step would also be relatively familiar – it is the process of downloading and customizing a recovery image in the form of an ISO file. It can be located in the Bacula Systems’ customer area and it has the following name:

  • LinuxBMR-rescue-amd64-2.0.0.iso

This image can be either burned to a CD/DVD or written to a bootable USB device, depending on the client’s personal preference.

Booting using the recovery image is the first step in an actual bare metal recovery process, and it may differ depending on whether you need to access BIOS to change the priority of boot devices or you can open that menu without going into BIOS, depending on the hardware manufacturer.

The first visual representation of the recovery process that a client would be able to see is the Isolinux language selection screen which should look similar to the example below. It can be navigated using standard arrow keys, and the “selection” key is Enter by default.

isolinux language selection screen

It is worth noting that this screen only lets you choose the language for your Linux Desktop environment, and the only language Bacula’s Bare Metal Recovery tool works in is English. After you have chosen the language from the list above, you would be transferred to the BMR boot screen, as shown below.

the bmr boot screen

However, there is another task that needs to be done here, and that is choosing the correct keymapping layout. It can be done by pressing F3 on that same page and choosing the layout that the client prefers with “Enter”.

the keymap selection screen

Once the keymap settings have been defined, the BMR boot screen is going to appear again, and choosing the “Start Bacula LinuxBMR” option would initiate the graphic desktop environment to proceed with the bare metal recovery task. Once the graphical interface is fully loaded, it is recommended to verify if the network settings of the environment are correct, since it is possible that everything was reset after loading this new environment. To open the Network Settings window, the user would have to click on the Network icon within the Linux environment located to the left of the clock at the bottom of the screen and then choose “Connection Information”.

the bmr system environment

The “Bacula Rescue” icon is the starting point for the BMR process once the proper network configuration is ensured. From now on, quite a lot of the menus are going to be somewhat similar to examples from the Windows bare metal recovery guide, starting with the “Welcome” screen, as shown below.

bacula linux bare metal recovery screen #1

The rest of the BMR wizard screens are going to be shown in a numerical order for easier reading comprehension.

  1. The first page that a client sees after going past the “Welcome” screen is the initial setup page that includes client’s name-password combination, director’s name-address combination, and more. All of these parameters are loaded directly from the ISO file and could have been modified beforehand (using the Client resource that was created as the first step of this process) – and it is also possible to modify them at this exact screen.
    acula linux bare metal recovery screen #2
  2. At this step, the system checks if the client daemon is running and if it is accessible from the Director – if even a single error pops up, then the process would not be able to continue. A client getting past this screen means that all of these parameters were configured correctly. The following screen shows a list of clients that the Director can detect, and the client would have to choose one to proceed.
    bacula linux bare metal recovery screen #3
  3. The next screen showcases different backups that were created under the chosen client – and the client would have to choose a BMR-enabled backup to proceed. The status of the backup is shown by a capital letter after the date of the backup (with F meaning a completed backup), and a linuxbmr field would show if the backup in question can be used for BMR or not. If the chosen client does not have any backups created, the error message would show up and the client would then be sent back to the “client” screen without being able to proceed.
    bacula linux bare metal recovery screen #4
  4. The more difficult part of the setup begins right here. Once a suitable BMR-ready backup is chosen, the tool loads the disk layout information from the source host to reproduce that layout on the target host, followed by restoring the data from the backup to the target host and configuring the bootloader as a final step of the process. Disk mapping is the first part of this process – it is a part of the process in which a user has to make sure that every disk of the source host is allocated to a disk of the target host. A relatively simple interface allows for different disk allocation rules, and there is also an option to straight-up remove one or several volumes from the process, meaning that they are not going to be restored during the bare metal recovery process.
    bacula linux bare metal recovery screen #5
  5. Once disk partitions have been set up, another Bacula screen allows for these partitions to be modified and adjusted per-partition basis. Adding more partitions or removing them is not possible at this stage, the only option is to adjust them. Green-colored partitions have extra space left, while red partitions are overfilled and would have to be shrunk in size for the BMR process to proceed.
    acula linux bare metal recovery screen #6
  6. There are two partitioning methods available in Bacula Linux Bare Metal Recovery – Automatic and Manual. Automatic partitioning attempts to rearrange existing partitions without any input from the client, and that way it is possible to skip a single step of this instruction. For a more personalized approach, it is possible to choose Manual partitioning, which results in the following screen. An experienced user can use this screen to manually change specific partition rules or restrictions, allowing for more flexibility down the road.
    bacula linux bare metal recovery screen #7
  7. One last step to go through before initiating the restoration is to match the volumes from inside of the backup with the newly-partitioned volumes on the target host. Double-clicking on every “none” position on the “Restore to” category allows users to specify where this specific object would be restored to.
    bacula linux bare metal recovery screen #8
  8. The next part of the process is the entire restoration procedure, it can be monitored with a status screen as shown in the example below. This window shows the elapsed time, the estimated remaining time, as well as the general percentage status of the recovery process.
    bacula linux bare metal recovery screen #9
  9. The recovery process is technically completed now, but there are still a few more operations to go through. First of all, the picture below is the screen that is shown when the main recovery operation has been completed. It showcases a “success” message and a general log of errors and other issues that happened during the restoration phase, if any. The last step of the BMR process is to perform boot setup – it is done in a similar fashion to how partitioning could be done in the example above. It allows for two different approaches – automatic and manual. The automatic boot setup process allows the plugin to try and set up everything for the client, while the manual offers a high degree of customization to an experienced user to work with.
    bacula linux bare metal recovery screen #10
  10. If the automatic boot setup was chosen, the client then proceeds directly to the next, and final, screen of the Bacula wizard. If the manual boot setup was chosen instead, then the user would see the additional screen similar to how image #7 – with multiple boot scripts that can be customized and/or launched, with another segment of a window being delegated for boot script output results.
    bacula linux bare metal recovery screen #11
  11. Once the boot setup process has been completed, all users shall see the final screen of the Bacula Linux Bare Metal Recovery wizard, offering a list of errors and warnings that were detected during or after the recovery process. Clicking “Finish” is the final step of this manual.
    bacula linux bare metal recovery screen #12


Bare metal recovery is an essential part of any company’s disaster recovery plan – a set of guidelines and procedures created to mitigate or prevent potential data-related issues such as cyber-attacks, data corruption, data theft, and so on. A disaster recovery plan template is crucial to creating these plans since these plans and strategies tend to be somewhat complicated and may take a long time to create by hand from scratch. Bacula provides a solution that comes with exceptionally high security and is used by the most secure-conscious organizations in the West. More information on why and how to protect backup and recovery from attack is available here.

About the author
Rob Morrison
Rob Morrison is the marketing director at Bacula Systems. He started his IT marketing career with Silicon Graphics in Switzerland, performing strongly in various marketing management roles for almost 10 years. In the next 10 years Rob also held various marketing management positions in JBoss, Red Hat and Pentaho ensuring market share growth for these well-known companies. He is a graduate of Plymouth University and holds an Honours Digital Media and Communications degree, and completed an Overseas Studies Program.