Carbonite Support > Hyper-V Backup

Hyper-V Backup

  • This article is for Windows only

Summary:

Carbonite Safe Server Backup (CSSB) supports backup and restore of virtual machines hosted by Hyper-V server installations on Windows Server 2008, Windows Server 2012, Windows Server 2016 and Windows Server 2019. Servers in core configuration are not supported. Hyper-V backups support full backups on Windows Server 2008 and higher. Incremental backups are supported on Windows Server 2008 R2 and higher. Differential backups are not supported on any platform.

Solution:

Considerations for Hyper-V Backups

  • The Initial Store (InitialStore.xml) is always backed up and will not appear in the "Backing Up" list.
  • All Virtual Machines in Hyper-V may be selected
    • With all VMs selected, newly added VMs will be automatically detected and backed up.
    • With all VMs selected, VMs that are removed from Hyper-V will be automatically removed from the backup.
  • Virtual Machines may be selected for backup individually.
    • When selecting VMs individually, VMs are not automatically added or removed from the backup.
    • While all virtual hard disk (VHD) files associated with the virtual machine will be displayed, you cannot choose individual VHD files. Selecting one of a virtual machine’s associated VHD files will select all others automatically.
    • If there are multiple Hyper-V backup sets configured within CSSB, they can run simultaneously, but should be started at least one minute apart to allow time for VSS Snapshot creation.
      • A virtual machine should not be backed up in more than one backup set.
  • VMs are backed up by one of two methods.
    • Child VM Snapshot – This method uses the Volume Shadowcopy Service (VSS) inside a child VM. This allows the VM to be backed up without forcing it into a saved state.
      • This is the default backup method. If a Child VM Snapshot cannot be taken, a Saved State backup is taken instead.
      • Child VM Shapshot backups have additional requirements, as outlined in the collapsible section below.
    • Saved State – This method briefly places each VM into a saved state so that a snapshot can be taken. Once the snapshot is taken, the VM is returned to its previous state.
      • This method is used if the Child VM Snapshot method cannot be performed.
  • If Microsoft SQL Server, Exchange, or SharePoint is running on a Virtual Machine, then transaction logs for those databases will be truncated when a Hyper-V backup occurs.
    • Truncation will occur as a part of both full and incremental backups.
    • Truncation will occur during both Saved State and Child Snapshot backups.
    • Truncation can affect the ability to perform backups of these databases from within the child VM.

The sections below are collapsed. Please click the section title to open / close a particular section.

Requirements

The following requirements must be met for Hyper-V backups to function.

General

  • The Hyper-V VSS Writer must be started.

Backup

  • During installs, CSSB will automatically install and start the Carbonite Safe Server Hyper-V Service on 64-bit systems running Hyper-V.
    • This service allows CSSB to take and maintain incremental backups for Hyper-V. Any interruption will cause incremental backups to fail, as described below.
      • The Carbonite Safe Server Hyper-V Service must be running at the time of the most recent successful full backup. If it was not running at that time, attempts to perform incremental backups will fail.
      • If the service is stopped, restarted, or suffers any interruption after the full backup, subsequent incremental backups will fail until a new full backup is performed.
      • The errors associated with these failures will prompt the user to run a new full backup.
  • The virtual hard disk files for each VM must be stored locally or on SMB3 network shares. See the Requirements for VSS Snapshots on a SMB3 Network Share section below for more information.

Restore

  • Restore of Hyper-V virtual machines and Host Configuration must be done to the same version of Windows as took the backup.
    • For example, if the original Hyper-V backup was taken on Windows Server 2008 R2, the restore must be done to Windows Server 2008 R2.

Additional Requirements for Child VM Snapshot backups

The following requirements must be met for Child VM Snapshot backups to function.

  • Backup (volume snapshot) Integration Service must be installed and running on the child VM.
    • The service name is Hyper-V Volume Shadow Copy Requestor.
  • The child VM must be in the running state. VMs that are not running always use the Saved State backup method.
  • The Snapshot File Location for the VM must be located on the same volume in the host operating system as the VHD files.
    • Example: If the VHD files are on C:\, the Snapshot File Location must be on C:\
  • All volumes in the child VM must be basic disks. Dynamic disks are not supported by the Child VM Snapshot method.
  • All disks in the child VM must use a file system that supports snapshots, such as NTFS or ReFS.

Unsupported Configurations

Hyper-V backups are not supported in the following cases.

  • Windows "Core" Servers running Hyper-V are not supported.
  • Cluster Shared Volumes are not supported.
Requirements for VSS Snapshots on a SMB3 Network Share

CSSB is able to take snapshots of files located on network shares configured with the SMB3 protocol. This allows backup of open, in-use, and locked files that exist on these shares.

The following requirements must be met.

  • The following backup types allow VSS snapshots of data on a SMB3 network share:
    • File System
    • Microsoft SQL Server
    • Hyper-V (full backups only)
  • The application server on which Carbonite Safe Server Backup is installed and the file server that houses the data must both be running Windows Server 2012 or higher.
  • The application server and file server must be joined to the same Active Directory domain.
  • The File Server VSS Agent Service role service must be installed on the file server.
  • The amandabackup / CarboniteUser user (or the user specified in Tools; Network Location) must be a member of the Backup Operators and Administrators groups on both the application server and file server.
    • The amandabackup / CarboniteUser user is granted these roles by default during CSSB installation. If a different user account is specified in Tools; Network Location, please ensure this user has the correct roles.
      • If amandabackup / CarboniteUser (or the user specified in Tools; Network Location) has been created as a domain user, simply ensure that amandabackup / CarboniteUser is a member of both groups on both machines.
        • In some environments, you may have to add amandabackup / CarboniteUser (or the user specified in Tools; Network Location) to the local Backup Operators and Administrators groups instead of using the domain groups.
      • If amandabackup / CarboniteUser (or the user specified in Tools; Network Location) has been created as a local user on the CSSB system and does not exist on both machines, you must manually create an identical user account on any system where it does not exist.
        • Use the same password for all systems.
        • Ensure that the user account is a member of the Backup Operators and Administrators groups on all systems.
  • The amandabackup / CarboniteUser user (or the user specified in Tools; Network Location) must have read-only or greater access to the file server.
    • It is recommended to give Full Control to this user account.

A snapshot cannot be created if these requirements are not met. If you are attempting a Hyper-V or Microsoft SQL Server backup, the backup will fail immediately without a snapshot.

If you are attempting a File System backup, CSSB will attempt to copy the files even if a snapshot cannot be created. Open, locked, and in-use files will fail to back up, but the backup as a whole will progress unless too many files cannot be backed up. Please refer to this Knowledge Base article.

You can read more about Hyper-V backups here: http://msdn.microsoft.com/en-us/library/dd405549%28v=vs.85%29.aspx.

Within the CSSB User Interface, you will notice the option to Back up a running VM only if its hot backup can be performed. This special option is designed to keep VMs running smoothly during backup. If enabled, CSSB will skip backup of a running VM when the Child VM Snapshot method cannot be performed.

Feedback