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Title
How to backup non VSS-aware applications -
Description
Backing up machines with an Agent engages Microsoft VSS to put supported applications into a consistent state during backup. This option ensures that all application write requests in the machine's memory are committed to disk before the snapshot is taken. This ensures the application data can be reliably recovered from the backup.
However, there are applications that are not VSS aware. In cases where you are backing up servers that host non VSS-aware applications, custom quiescing scripts can be used to achieve application-consistent backups.
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Cause
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Resolution
Windows Registry Disclaimer:
Quest does not provide support for problems that arise from improper modification of the registry. The Windows registry contains information critical to your computer and applications. Make sure you back up the registry before modifying it. For more information on the Windows Registry Editor and how to back up and restore it, refer to Microsoft Article ID 256986 “Description of the Microsoft Windows registry” at Microsoft Support.
PowerShell Scripting Disclaimer:
This script is provided "as is" for the purpose of illustrating how product tasks may be performed in conjunction with PowerShell. Support shall not be liable for any direct, indirect, incidental, consequential, or other damage alleged in connection with the furnishing or use of this script or of the principles it demonstrates. See PowerShell Scripting Support for more information.
Agent-Based Protection
With agent-based protection, a method is provided to execute a script before and after transferring a snapshot.
To run a custom quiescing script on the protected server:
- Log into the protected server
- Verify that the following regkey exists: HKLM\SOFTWARE\AppRecovery\Agent\PowerShell\ScriptsDirectory
- Check that the directory specified in the regkey exists (Typically it is C:\ProgramData\AppRecovery\Scripts). Create the directory if it does not exist.
- In C:\ProgramData\AppRecovery\Scripts create 2 empty text files called PreTransferScript.ps1 and PostTransferScript.ps1 (make sure that the .txt extension is not present)
- Edit the scripts to fit your custom quiescing needs.
- There is no need to restart the Agent service after the scripts have been created.
The PreTransferScript.ps1 and PostTransferScript.ps1 can be used to call other scripts or execute statements.
As an example, in KB142501, these scripts are used to quiesce an older Oracle DB.
- 2 Oracle SQL scripts are created in addition to the Pre & Post transfer scripts.
- After the backup task begins, the scripts directory is checked for the existence of the pre & post transfer scripts.
- The backup process executes PreTransferScript.ps1 which in turn executes an Oracle SQL script to place Oracle into a quiesced state.
- After the backup transfer has completed, PostTransferScript.ps1 is used to execute the second Oracle SQL script to place Oracle back into a normal state.
Agentless Protection
With agentless protection, Rapid Recovery relies on VMware tools, VMware's snapshot process and VDDK API's.
VMware has provided a way to execute scripts prior to taking and after deleting a VMware snapshot. This allows for the execution of custom quiscing scripts for non vss-aware applications.
To prepare a VM to use custom quiescing scripts:
- Verify that VMware tools is installed and running on the virtual machine.
- After VMware tools have been installed, depending on the version of ESXi you are running, you may need to create the backupscripts.d folder.
- Place the custom quiescing script in the specified script directory.
Default diretories for scripts on Windows virtual machines.
Version of ESXi Custom quiescing script directory ESXi 5.0 C:\Windows\ C:\Program Files\VMware\VMware Tools\backupScripts.d\ ESXi 5.1 and ESXi 5.5 C:\Windows\
C:\Windows\Scripts for non-Windows virtual machines.
- Pre-freeze: /usr/sbin/pre-freeze-script
- Post-thaw: /usr/sbin/post-thaw-script
If you are using multiple scripts in the backupScripts.d folder, they will be executed in alphabetical order during the freeze phase and in descending alphabetical order during the thaw phase.
If you are using the backupScripts.d folder, you can have a single bat file that can detect whether to run the freeze or thaw phase. For example, you can have the following in a bat file. The italicized text can be replaced to fit your needs.
echo off
if "%1" == "freeze" goto doFreeze
goto doThaw
:doFreeze
call c:\windows\pre-freeze-script.bat
goto EOF
:doThaw
call c:\windows\post-thaw-script.bat
:EOFAs an example, lets assume that a Domino server needs to be backed up.
- A pre-freeze script has been created and placed in the proper script directory.
Here is a sample pre-freeze script that will drop connected users and will also flush the cache for a Domino server.
"C:\Program Files\IBM\Lotus\Domino\nserver.exe" -c "drop all"
timeout /t 5 /nobreak
"C:\Program Files\IBM\Lotus\Domino\nserver.exe" -c "dbcache flush"
timeout /t 5 /nobreak- Rapid Recovery will begin the backup process and will issue a VMware API command to create a quiesced snapshot.
- The vSphere host will begin the VMware snapshot process and will execute the pre-freeze scripts via the VMware tools that is installed within the guest.
- Once the pre-freeze script has completed, the VMware snapshot will be created. This should leave the DB in a consistent state within the parent virtual machine disk that will be backed up by Rapid Recovery.
- After the backup is complete, another VMware API command will be issued to delete the VMware snapshot. Since there are no thaw scripts in this example, no scripts will be executed.