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Product Version: 9.0

Last Modified: 29 August 2019

Problems

  • When running a physical machine backup job in the app-aware mode set as Enabled (proceed on error), the following error appears: 

Quiesced snapshots of the "X" machine volumes cannot be created.
Quiesced (application-aware) snapshots of this machine volumes cannot be created. The physical machine will be processed without quiescing. This may influence resulting recovery point reliability

  • When running a physical machine backup job in the app-aware mode set as Enabled (fail on error), the following error appears: 

Backup/Replication of the "X" machine volumes has failed.
Quiesced (application-aware) snapshots of this physical machine volumes cannot be created

Background

If App-aware mode is enabled for a physical machine backup job, NAKIVO Backup & Replication triggers guest OS quiescing to ensure application data is consistent. This requires credentials to source physical machines and VSS/LVM must be properly configured. Depending on the App-aware mode setting, the processing of a physical machine can either continue or fail in case application quiescing error is encountered.

Application aware backup for Windows is done via VSS Driver integration. NAKIVO Backup & Replication requests the VSS Driver to create a quiesced snapshot. VSS Driver uses Volume Shadow Copy service (VSS) inside of a Windows physical machine to freeze I/O requests of applications inside of the operating system (OS). If OS quiescing fails to create an application-consistent snapshot, NAKIVO Backup & Replication displays one of the above errors.

You can perform application aware backup for Linux via custom scripts. You need to put your custom scripts called pre-freeze-script and post-thaw-script into /usr/sbin directory and give them the execute permission. pre-freeze-script and post-thaw-script scripts require the root permission to be executed. For more details on backing up Linux machines see Application-aware Mode for Linux VMs.

Possible Causes

The errors may be caused by:

Configuration:

  • Incorrect configuration of the OS

  • Incorrect OS credentials
  • Incorrect Windows firewall configuration on the machine where the Director is installed

  • Incorrect Linux firewall configuration on the machine where the Director is installed

Volume Shadow Copy Service (VSS)

  • Required services are not started/running
  • VSS Provider is not supported
  • Insufficient permissions on the VSS
  • VSS writers are not stable

Custom Scripts

  • Failure to detect custom scripts

Solutions

Configuration

Make sure that:

  • Your OS is supported for application-aware processing

  • OS firewall allows access to the default TCP port 9446, or a custom port you specified during product deployment, on the machine where the Director is installed

  • The provided OS credentials are correct

Volume Shadow Copy Service (VSS)

  • Make sure that you meet all of the prerequisites of VSS: 

    When idle, ensure that:

      • COM+ System Application is listed as Started and that the startup type is listed as Manual.
      • COM+ Event System service is listed as Started and that the startup type is listed as Automatic.
      • Volume Shadow Copy service is not running and the startup type is listed as Manual.
      • Microsoft Software Shadow Copy Provider service may or may not be started. Ensure that the startup type is listed as Manual.

    During the backup, ensure that:

      • COM+ System Application is listed as Started and that the startup type is listed as Manual.
      • COM+ Event System service is listed as Started and that the startup type is listed as Automatic.
      • Volume Shadow Copy service may or may not be started. Ensure that the startup type is listed as Manual.
      • Microsoft Software Shadow Copy Provider service startup type is listed as Manual.
  • When all VSS requirements are met, make sure you are using the Microsoft Software Shadow Copy Provider. You can check the VSS Providers by running the following command: C:\Users\Workstation> vssadmin list providers
  • Check the permissions on the account with which the VSS service is configured to log on. Refer to the corresponding Microsoft Knowledge Base article to know how to troubleshoot service permissions. Keep in mind, that a third-party VSS provider may interfere with the quiescing operation. If this happens, uninstall any third-party VSS providers

    Note

    The VSS and vssadmin utility are bundled with the Microsoft OS.  Therefore, If the vssadmin utility is reporting errors, this may indicate a pre-existing issue with the VSS. Refer to Microsoft support before proceeding with the next troubleshooting steps.

  • Ensure that all of the VSS writers are stable and they are not reporting an error by running the following command: C:\Users\Workstation> vssadmin list writers.
    The last line of the output should be the following: Last error: No error.
    If you are experiencing difficulty backing up information from such applications as Microsoft Exchange, Microsoft SQL, and Active Directory, make sure that all necessary VSS writers are also installed with these components.
    If the issues persist, visit http://support.microsoft.com/ to see if there are any updates for VSS or patches. 

LVM and Custom Scripts

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