[pve-devel] [RFC qemu/storage/qemu-server/container/manager 00/23] backup provider API

[Jonathan Nicklin]

Hi Fiona,

Would adding support for offloading incremental difference detection
to the underlying storage be feasible with the API updates? The QEMU
bitmap strategy works for all storage devices but is far from
optimal. If backup coordinated a storage snapshot, the underlying
storage could enumerate the differences (or generate a bitmap).

This would allow PBS to connect directly to storage and retrieve
incremental differences, which could remove the PVE hosts from the
equation. This "storage-direct" approach for backup would improve
performance, reduce resources, and support incremental backups in all
cases (i.e., power failues, shutdowns, etc.). It would also eliminate
the dependency on QEMU bitmaps and the overhead of fleecing.

Theoretically, this should be possible with any shared storage that
can enumerate incremental differences between snapshots: Ceph,
Blockbridge, iSCSi/ZFS?

Thoughts?