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Automated Volume Snapshot as Backup

When Enable Provider Backup is No, CMP does not run a separate backup engine. It automates scheduled CloudStack volume snapshots on the VM root disk and exposes them in CMP as the VM backup and recovery mechanism — schedule, retain, restore, and bill via the VM Backup package.

Typical for CloudStack before 4.20, or when CloudStack Backup & Recovery (B&R) is not configured.

Root volume snapshot — not a VM snapshot

CMP uses Automated Volume Snapshot as Backup. Internally, the scheduler takes a snapshot of the VM root volume — not a full VM (instance) snapshot.

VM snapshots have hypervisor- and environment-specific restrictions (memory capture, storage type, concurrent volume operations, and similar). Root volume snapshots are the consistent recovery mechanism CMP relies on for this backup path.

Additional data volumes on the VM are not included in automated backup snapshots unless your deployment configures otherwise.

Not enabled by default

Backup is disabled at onboarding. The provider must choose this model and complete CloudStack snapshot prerequisites first. See Backup — provider decision.

Which backend am I on?
You are here if…Otherwise use…
Enable Provider Backup = No in Cloud Provider SetupCloudStack B&R-Based Backup when Enable Provider Backup = Yes
CloudStack before 4.20, or no B&R plugin configured

Concepts​

VM Backup vs manual snapshots​

VM Backup (CMP product)Manual snapshots
PurposeScheduled, retained, billable recovery pointsOne-off save before a change
Under the hoodAutomated root volume snapshotsCustomer-triggered CloudStack VM or volume snapshots
Who sets scheduleCustomer (or policy) in CMP on the VMCustomer triggers each snapshot
BillingVM Backup package (BACKUP) — hourly per GBVolumes Snapshot package if billed
CMP pathVM → BackupVM / Volume → Snapshots

Manual snapshot behaviour is documented under Snapshots. This page covers Automated Volume Snapshot as Backup and the CloudStack volume snapshot mechanics it relies on.

How Automated Volume Snapshot as Backup works​

Customer enables backup / schedule on VM (CMP)
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CMP calls CloudStack volume snapshot API on the VM root volume
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Snapshots stored in CloudStack secondary storage
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CMP bills via VM Backup package; enforces retention
  • CMP is a scheduler and billing layer — not a backup engine.
  • Recovery uses CloudStack root volume snapshots created on a schedule.
  • The customer does not manage snapshot jobs in CloudStack — only in CMP.
  • When backup is disabled, CMP stops billing and deletes all associated snapshots.

Volume snapshots (CloudStack)​

A volume snapshot is a point-in-time capture of a disk (root or data volume). It does not capture CPU or memory state.

  • Automated backup on this path snapshots the root volume only
  • Snapshots can also be taken manually for root disks and data disks
  • Taking snapshots of a running VM's root disk may require CloudStack global settings on KVM — see below
KVM and root volume snapshots

If root volume snapshots fail on running KVM VMs, set kvm.snapshot.enabled = true in CloudStack Global Settings. This is often required for Automated Volume Snapshot as Backup on KVM.

Supported hypervisors: XenServer, VMware vSphere, KVM
Not supported: Oracle VM (OVM)

Restoring a volume snapshot​

OptionDescription
Create Volume from SnapshotMount restored volume to recover specific files
Create Template from SnapshotBoot a new instance from the template (root disk only)
Revert to SnapshotRevert volume to snapshot state (storage/hypervisor dependent)

VM / instance snapshots (CloudStack reference)​

Full VM (instance) snapshots capture instance state including optional memory. CMP automated backup does not use this path — it is documented here because manual snapshot and CloudStack admin workflows may still reference instance snapshots.

  • Memory capture supported only on NFS storage
  • For other storage types, snapshot with memory will fail
  • Supported on: VMware, XenServer, KVM (NFS only for memory)
  • Cannot attach or delete volumes when stored snapshots exist — delete snapshots first
  • Service offering changes discard memory-included snapshots automatically
  • Cannot take VM and volume snapshots simultaneously on the same instance

Reference: CloudStack — Instance snapshots

Product behaviour (schedule, retention, billing)​

The VM Backup product on this path is scheduled root volume snapshot automation — exposed to customers as backup in CMP.

Retention​

  • Each schedule specifies how many recurring snapshots to retain
  • Oldest snapshots are deleted automatically when the limit is exceeded
  • Set backup_limit in global settings for maximum snapshots per VM

Billing​

  • Billed hourly based on VM backup storage size
  • Rate: hourly_rate × storage_GB
  • Billing starts when backup is enabled; stops when disabled
  • All snapshots are deleted when backup is disabled

Package setup: VM Backup packages

Restrictions​