[pve-devel] [PATCH SERIES storage/qemu-server/-manager] RFC : add lvmqcow2 storage support

[Alexandre Derumier via pve-devel <pve-devel@lists.proxmox.com>]

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From: Alexandre Derumier <alexandre.derumier@groupe-cyllene.com>
To: pve-devel@lists.proxmox.com
Subject: [PATCH SERIES storage/qemu-server/-manager] RFC : add lvmqcow2 storage support
Date: Mon, 26 Aug 2024 13:00:18 +0200
Message-ID: <20240826110030.1744732-1-alexandre.derumier@groupe-cyllene.com>

This patch series add support for a new lvmqcow2 storage format.

Currently, we can't do snasphot && thin provisionning on shared block devices because
lvm thin can't share his metavolume. I have a lot of onprem vmware customers
where it's really blocking the proxmox migration. (and they are looking for ovirt/oracle
virtualisation where it's working fine).

It's possible to format a block device without filesystem with qcow2 format directly.
This is used by redhat rhev/ovirt since almost 10year in their vsdm daemon.

For thin provisiniong or to handle extra size of snapshot, we need to be able to resize
the lvm volume dynamically.
The volume is increased by chunk of 1GB by default (can be changed).
Qemu implement events to sent an alert when the write usage is reaching a threshold.
(Threshold is 50% of last chunk, so when vm have 500MB free)

The resize is async (around 2s), so user need to choose a correct chunk size && threshold,
if the storage is really fast (nvme for example, where you can write more than 500MB in 2ss)

If the resize is not enough fast, the vm will pause in io-error.
pvestatd is looking for this error, and try to extend again if needed and resume the vm


pve-storage:

Alexandre Derumier (5):
  add lvmqcow2 plugin
  vdisk_alloc: add underlay_size option
  add volume_underlay_resize
  add refresh volume
  add volume_underlay_shrink

 src/PVE/Storage.pm                |  52 +++++-
 src/PVE/Storage/LVMQcow2Plugin.pm | 272 ++++++++++++++++++++++++++++++
 src/PVE/Storage/Makefile          |   3 +-
 src/PVE/Storage/Plugin.pm         |  20 +++
 4 files changed, 344 insertions(+), 3 deletions(-)
 create mode 100644 src/PVE/Storage/LVMQcow2Plugin.pm


qemu-server:

Alexandre Derumier (6):
  lvmqcow2: set disk write threshold
  qm cli: add blockextend
  qmevent: call qm disk blockextend when write_threshold event is
    received
  migration: refresh remote disk size before resume
  qemu_img_format: lvmqcow2 is a path_storage
  clone: allocate && shrink lvmcow2 underlay

 PVE/CLI/qm.pm                         |  57 ++++++++++
 PVE/QemuMigrate.pm                    |  13 +++
 PVE/QemuServer.pm                     | 154 +++++++++++++++++++++++++-
 qmeventd/qmeventd.c                   |  27 +++++
 test/MigrationTest/QemuMigrateMock.pm |   2 +
 5 files changed, 251 insertions(+), 2 deletions(-)


pve-manager:

Alexandre Derumier (1):
  pvestatd: lvmqcow2 : extend disk on io-error

 PVE/Service/pvestatd.pm | 62 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)


-- 
2.39.2



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