This posting is the second in a serie by Altaro about backup for Hyper-V. The first posting can be read here. It gives a good insight about backup, VSS and redirected access mode.
When is Application-Consistent Backup Vital? Not all situations require an application-consistent backup. Things such as file and print servers will be fine with crash-consistent and possibly inconsistent backups. If your application doesn’t provide a VSS writer, there might not even be a way to get an application-consistent backup of it while its containing machine is live. The most common need for application-consistent backups is the usage of database-backed applications.
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