Limitations for KVM backups
The following limitations exist for backups of KVM hosts.
You cannot backup the same KVM virtual machine concurrently.
The VMs without virtual disks cannot be protected.
The following QCOW2 image attributes are not supported:
Compressed cluster
Encrypted disks
Incremental backups are supported only when BLIB is enabled.
Changed block tracking (CBT) is supported only for QCOW2 disk types.
CBT is supported with QCOW2 v3 or later. Older versions of QCOW2 do not persist the dirty blocks bitmap. Incremental backups of older qcow2 versions back up the full disk.
If a QCOW2 disk's bitmap is in an inconsistent state, incremental backups back up the full disk.
The dirty bitmap tracking should be persistent as long as the QEMU process on the KVM host is not terminated. If this process is shut down, incremental backups back up the full disk.
Changed blocks are not captured for raw and block device disk types. Incremental backups of these disk types back up the full disk.
Manual snapshot / checkpoint manipulation outside of NetBackup can break incremental chains.