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Component-Level Backup Introduced in Alike 3.5
Alike 3.5 introduced component-level support for VSS snapshots in our Q-Hybrid backup technology. Q-Hybrid backups are available for XenServer, Hyper-V, and Physical machines.
Q-Hybrid is a backup approach specific to compatible Microsoft guests and machines. It uses VSS (Volume Shadow Service) to capture the running state of the machine and prepare it for volume-level backup. For more information about Q-Hybrid, please see our overview article. Starting in Alike v3.5, you have the option to enable component-level VSS backup, on a per-machine basis. If you enable component-level VSS, Alike will dynamically generate a list of all VSS writers and components required by the snapshot and will add each one to its VSS snapshot request. If one or more of these components has errors, Alike will fail the job and report and error in its job log.
Furthermore, when component-level backup is enabled, Alike will call back each component after the job has competed with a success or failure status. This allows components to perform application-specific cleanup tasks, such as log rotation, upon successful backup.
Without the vss.conf file or prior to v3.5, Q-Hybrid will use default Windows VSS behavior to invoke all VSS writers and components needed for the selected volumes. While some writer misconfigurations can cause Alike to be unable to take a VSS snapshot, other writer errors are reported to the target machine's event log without affecting the Alike job.Furthermore, when component-level backup is enabled, Alike will call back each component after the job has competed with a success or failure status. This allows components to perform application-specific cleanup tasks, such as log rotation, upon successful backup.
To enable component-level VSS backup for a machine:
Simply create an empty file named "vss.conf" in the QSI subfolder of the Windows directory. On most machines, the file to create is c:\windows\QSI\vss.conf.
To stop component-level VSS on this machine:
Simply delete the vss.conf file on the target machine. This will revert your Q-Hybrid jobs back to using the standard VSS snapshot approach.