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Foreword

OpenStack recognises two types of resources on their clouds:

1. Instances, which correspond to the servers or VMs. These can be image-backed, if the VM was booted from an image, or volume-backed, if it was booted from a volume. Instances are managed via the OS Glance service.
2. Volumes, which correspond to storage disks which can be attached to VMs. Root disk are a special case as VMs are booted from them. Volumes are managed by the OS Cinder service.

Before backing up resources in OpenStack, it's important to understand the difference between two primary methods:

1. Snapshots: These are delta copies of the root volumes attached to the VMVMs or volumes. Snapshots are not full copies and rely on the original volume resource for restoration, so they are mostly useful for accident recovery. They're managed through the Cinder service.
2. Backups: These are point-in-time copies of the VMs or volumes attached to VMs. Backups preserve the data within a volume resource and can be used to restore the volume it to the exact state it was in when backed up. They're ideal for data recovery and are managed through the Cinder service.

Choose the appropriate method based on your recovery needs: snapshots for accident prevention and recovery or backups for full data security and recovery.

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Backing up VMs

VM Snapshots

Anchor
Snapshots Snapshots

To take a snapshot of a VM for later recovery or replication, one must take a snapshot of the root and other attached volumes as well as store the image configuration.  The list of VMs/servers than can be used for the snapshot can be found with:

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