A Practical Look at QEMU's Block Layer Primitives - Kashyap Chamarthy, Red Hat

No ratings

Presented at LinuxCon 2016 by

Kashyap Chamarthy

QEMU's block subsystem forms the foundation for some of the essential virtualization storage features -- live disk mirroring, incremental backups, Qcow2 disk image Chains, and point-in-time snapshots to name a few. These features are driven by an underlying set of QEMU primitives, which are typically exposed via an external virtualization API, such as libvirt. This talk will walk-through some of these primitives (e.g. drive-backup, drive-mirror, blockdev-backup, etc), discuss their invocation -- either directly via the QMP (QEMU Machine Protocol) interface or the libvirt APIs; understand how some of them could be combined to perform a specific operation (e.g. how live storage migration is achieved via a combination of QEMU's built-in NBD (Network Block Device) server plus the disk mirroring mechanism); other practical scenarios in the context of higher-level projects (OpenStack Nova).