[PATCH-SERIES v4 pve-storage/qemu-server/pve-qemu] add external qcow2 snapshot support

Alexandre Derumier alexandre.derumier at groupe-cyllene.com
Tue Mar 11 11:28:48 CET 2025


This patch series implement qcow2 external snapshot support for files && lvm volumes

The current internal qcow2 snapshots have bad write performance because no metadatas can be preallocated.

This is particulary visible on a shared filesystem like ocfs2 or gfs2.

Also other bugs are freeze/lock reported by users since years on snapshots delete on nfs
(The disk access seem to be frozen during all the delete duration)

This also open doors for remote snapshot export-import for storage replication.

Changelog v4:
     - use blocknode fixed names with sha1+base62
     - use block-stream for snapshot delete
     - qemu : use throttle qom object (no more x-throttle )
     - various cleanup && refactoring from fabian comments

MAIN TODO:
    - convert/implement all the backup code, dirty dirty bitmap, ...
    - iscsi blockdev syntax
    - ceph keyring as blockdev option
    - unit tests
    


storage.cfg example:

dir: local2
        path /var/liv/vz
        content snippets,vztmpl,backup,images,iso,rootdir
        snapext 1

lvm:test
        vgname test
        content images


pve-storage:

Alexandre Derumier (5):
  qcow2: add external snapshot support
  lvmplugin: add qcow2 snapshot
  storage: vdisk_free: remove external snapshots
  lvm: lvrename helper: allow path
  lvm: add lvremove helper

 src/PVE/Storage.pm                 |  22 ++-
 src/PVE/Storage/DirPlugin.pm       |   1 +
 src/PVE/Storage/LVMPlugin.pm       | 251 ++++++++++++++++++++++++++---
 src/PVE/Storage/Plugin.pm          | 232 +++++++++++++++++++++-----
 src/test/run_test_zfspoolplugin.pl |  18 +++
 5 files changed, 456 insertions(+), 68 deletions(-)

qemu-server:

Alexandre Derumier (11):
  blockdev: cmdline: convert drive to blockdev syntax
  blockdev : convert qemu_driveadd && qemu_drivedel
  replace qemu_block_set_io_throttle with qom-set throttlegroup limits
  blockdev: vm_devices_list : fix block-query
  blockdev: convert cdrom media eject/insert
  blockdev: block_resize: convert to blockdev
  blockdev: nbd_export: block-export-add : use drive-$id for nodename
  blockdev: convert drive_mirror to blockdev_mirror
  blockdev: change aio on target if io_uring is not default.
  blockdev: add backing_chain support
  qcow2: add external snapshot support

 PVE/QemuConfig.pm                             |   4 +-
 PVE/QemuMigrate.pm                            |   2 +-
 PVE/QemuServer.pm                             | 632 +++++++++---------
 PVE/QemuServer/Drive.pm                       | 415 ++++++++++++
 test/MigrationTest/QemuMigrateMock.pm         |  10 +-
 test/cfg2cmd/bootorder-empty.conf.cmd         |  12 +-
 test/cfg2cmd/bootorder-legacy.conf.cmd        |  12 +-
 test/cfg2cmd/bootorder.conf.cmd               |  12 +-
 ...putype-icelake-client-deprecation.conf.cmd |   6 +-
 test/cfg2cmd/ide.conf.cmd                     |  23 +-
 test/cfg2cmd/pinned-version-pxe-pve.conf.cmd  |   6 +-
 test/cfg2cmd/pinned-version-pxe.conf.cmd      |   6 +-
 test/cfg2cmd/pinned-version.conf.cmd          |   6 +-
 test/cfg2cmd/q35-ide.conf.cmd                 |  23 +-
 .../q35-linux-hostpci-template.conf.cmd       |   3 +-
 test/cfg2cmd/seabios_serial.conf.cmd          |   6 +-
 ...imple-balloon-free-page-reporting.conf.cmd |   6 +-
 test/cfg2cmd/simple-btrfs.conf.cmd            |   6 +-
 test/cfg2cmd/simple-virtio-blk.conf.cmd       |   6 +-
 test/cfg2cmd/simple1-template.conf.cmd        |  11 +-
 test/cfg2cmd/simple1-throttle.conf            |  14 +
 test/cfg2cmd/simple1-throttle.conf.cmd        |  33 +
 test/cfg2cmd/simple1.conf.cmd                 |   6 +-
 23 files changed, 886 insertions(+), 374 deletions(-)
 create mode 100644 test/cfg2cmd/simple1-throttle.conf
 create mode 100644 test/cfg2cmd/simple1-throttle.conf.cmd

pve-qemu:

Alexandre Derumier (1):
  add block-commit-replaces option patch

 ...051-block-commit-add-replaces-option.patch | 137 ++++++++++++++++++
 debian/patches/series                         |   1 +
 2 files changed, 138 insertions(+)
 create mode 100644 debian/patches/pve/0051-block-commit-add-replaces-option.patch

-- 
2.39.5




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