Windows Server, since its first version, offers the possibility to perform a System State backup alongside the most usual System Image backup (not available on Windows Server 2003).
The differences between the two modes are huge but not clear to everyone.
A System Image backup is a copy of the system drives and, eventuall, of other drives, of a physical or a virtual machine.
This backup can be used to restore from the ground the full system and includes everything.
According to Microsoft, a System State backup includes the following:
- Boot files, including the system files, and all files protected by Windows File Protection (WFP)
- Active Directory (on a domain controller only)
- Sysvol (on a domain controller only)
- Certificate Services (on certification authority only)
- Cluster database (on a cluster node only)
- The registry
- Performance counter configuration information
- Component Services Class registration database
So it’s a far more lightweight backup: faster, with less disk occupation, but with reduced restore capabilities.
We suggest to perform System State backup only if you have already scheduled regular System Image backups. Otherwise, there could be real problems in case of disaster.