Reverse the first-parent diff of a3df317ae0,
including the feature branch compatibility and mover follow-up fixes.
Retain the independent multi-pool correctness fixes from #178 and migrate
their shared test fixture away from access-tier code.
Tolerate retired ILM keys and XML, read old v9 statistics while writing v8,
and document migration without moving objects or rewriting their metadata.
Include regression coverage using a historical scanner/writer v9 fixture.
Signed-off-by: Feng Ruohang <rh@vonng.com>
Keep NVMe/HDD pool pairs useful without remote tiering: promote objects that
are read often, demote previously moved objects once they go idle, and leave
the feature off until operators set a two-pool topology.
Signed-off-by: mr javad seydi <seydi.birjand@gmail.com>
Feng Ruohang