[pve-devel] [PATCH 0/4] Keep dirty-bitmaps for PBS during migration

[Stefan Reiter <s.reiter@proxmox.com>]

Allow dirty bitmaps to persist over a live migration, allowing incremental
backups even after a VM has been moved to another node.

Migrating the dirty-bitmaps themselves is supported natively by QEMU, only
requiring a fix for a bug leading to hangs when migrating bitmaps with a
granularity as low as we are using (see first patch).

The second and third patches are the interesting bits, implementing
"savevm"-style migration for all PBS state that is being kept in memory
(checksums).

The last patch brings it all together by enabling it in qemu-server when support
is detected (which is important, since we never want to enable "dirty-bitmaps"
capability on unpatched versions of QEMU, as that will lead to unrecoverable VM
hangs).

Compatility is maintained between all pve-qemu-kvm and qemu-server versions,
with the usual exception of not being able to migrate VMs started with a newer
QEMU version to a machine with an older one.


qemu: Stefan Reiter (2):
  migration/block-dirty-bitmap: fix larger granularity bitmaps
  PVE: Migrate dirty bitmap state via savevm

 include/migration/misc.h       |  3 ++
 migration/Makefile.objs        |  1 +
 migration/block-dirty-bitmap.c |  3 +-
 migration/pbs-state.c          | 92 ++++++++++++++++++++++++++++++++++
 pve-backup.c                   |  1 +
 qapi/block-core.json           |  9 +++-
 softmmu/vl.c                   |  1 +
 7 files changed, 108 insertions(+), 2 deletions(-)
 create mode 100644 migration/pbs-state.c

proxmox-backup-qemu: Stefan Reiter (1):
  add state serializing and loading functions

 Cargo.toml      |  1 +
 current-api.h   | 20 ++++++++++++++++++++
 src/commands.rs | 19 +++++++++++++++++++
 src/lib.rs      | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 74 insertions(+)

qemu-server: Stefan Reiter (1):
  migrate: enable dirty-bitmap migration

 PVE/QemuServer.pm | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

-- 
2.20.1