Description

QSD (QEMU Storage Daemon) is a split of the QEMU storage features from QEMU into a standalone component. This QSD component can provide the features that are usually only available to VMs (through QEMU), to any other consumer through interfaces like fs-mount (nbd, fuse), vhost-user-blk, etc.

With this, one can have qcow2, snapshots, bitmaps/incremental backup and all other block features from QEMU without QEMU and without a running VM.

Acceptance Criteria

This is the first TechPreview of QSD. It should possible for users and developers to enable it for experimentation and benchmark purposes.

• Start QSD through libvirt (running it in sync with QEMU is OK)
  • Consume QSD storage through vhost-user-blk in QEMU
  • Alongside non-QSD storage
    • Requires routing of some QMP commands to QSD
• Locally mount QSD storage using nbd and/or FUSE (manually, without libvirt)

There's no need to support advanced use-cases in this first version, such as:

• Running a standalone QSD process through libvirt
• Definitive APIs/XML or documentation
• Handling local mounting of storage from QSD (nbd and/or FUSE) via libvirt