The Windows snapshot service that MARS relies on to take consistent copies. On its own it does not provide backups.
Also called Volume Shadow Copy Service.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains VSS in context, with comparison tables and the common traps.
Terms in this definition
- snapshot
Captures a VM's disk state, power state, settings and, if requested, memory at a moment in time, using one delta disk per virtual disk. Snapshots should not be relied on as backups.
- Microsoft Azure Recovery Services agent
Usually installed on on-premises Windows machines, the MARS agent sends their files, folders and system state directly into a Recovery Services vault.
Related terms
- Hyper-V checkpoint
A snapshot of a Hyper-V VM's state at one moment. Production checkpoints use VSS in the guest; standard ones include what is in memory too.
- NTDS
On a domain controller, this covers ntds.dit (the AD DS database) with its logs, plus the NTDS folder, service and VSS writer.
- Previous Versions
Lists older copies of a file in Explorer, drawn from VSS shadow copies or, where an Azure file share is mounted, its share snapshots.
- Production checkpoint
Hyper-V's default kind, capturing data-consistent state through VSS, or a file system freeze for Linux guests, but no memory. Choosing ProductionOnly makes creation fail instead of quietly using a standard checkpoint.