Speaker
Description
Container storage commonly relies on directory overlays, filesystem-native subvolumes, or thin-provisioned block devices. We will explore another approach: exposing QCOW2 images directly as Linux block devices through a device-mapper target. QCOW2 is the standard virtual-disk format across much of the QEMU/KVM ecosystem. Its widespread adoption, mature tooling, and features such as backing-file chains, persistent bitmaps, and sparse allocation make it an attractive option for container storage as well.
But just having a nice loop device is not a complete solution. Container storage must also support essential operations such as snapshots, backups, and migration. This talk will show how we map these requirements onto existing device-mapper and Linux kernel capabilities, what is still missing, and which problems remain unsolved.