Reference
Do I need snagent?
It depends on the path: QCOW NFS, ZFS, and LINSTOR DRBD host-assisted modes require snagent; RAW Block does not use it.
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The Short Answer
Not for every path. QCOW NFS, ZFS, and LINSTOR DRBD host-assisted modes require a healthy snagent and can fail if it is unavailable. RAW Block does not use snagent and follows the full-source-read EBA path.
For qualified host-assisted modes, snagent prepares the source snapshot and supplies extent information so the SNA reads the identified extents.
When It Is Used
- Required when the selected CloudStack KVM mode is QCOW NFS, ZFS, or LINSTOR DRBD host-assisted protection.
- Not used for RAW Block - that backend uses the full-source-read EBA path instead.
- If the required snagent is absent or unavailable, the host-assisted backup can fail rather than automatically switching to a full-source-read path.
Related Docs
snagent Hypervisor Host AgentThe CloudStack KVM hypervisor host agent used for efficient host-assisted changed-block tracking.EBA Smart TransportThe SNA-side smart transport role that sends protected data to SHA and uses extent maps from snagent when available.CloudStack KVM OverviewHow Sendense protects CloudStack KVM environments with SNA, EBA-ST, and the optional snagent host agent.