[pve-devel] [PATCH container/guest-common/qemu-server 0/3] log when freezing or thawing the guest's fs

[Shannon Sterz]

On Fri Aug 29, 2025 at 1:43 PM CEST, Maximiliano Sandoval wrote:
> At the moment taking a snapshot without RAM does not log whether there was a freeze/thaw.
>
> This does not add an extra log line when making a Backup in snapshot mode.
>
> qemu-server:
>
> Maximiliano Sandoval (1):
>   log when issues a guest-fsfreeze command
>
>  src/PVE/QemuConfig.pm | 2 ++
>  1 file changed, 2 insertions(+)
>
>
> pve-container:
>
> Maximiliano Sandoval (1):
>   log when freezing/thawing filesystem
>
>  src/PVE/LXC/Config.pm | 2 ++
>  1 file changed, 2 insertions(+)
>
>
> qemu-server:
>
> Maximiliano Sandoval (1):
>   replication: remove logging when freezing/thawing
>
>  src/PVE/Replication.pm | 2 --
>  1 file changed, 2 deletions(-)
>
>
> Summary over all repositories:
>   3 files changed, 4 insertions(+), 2 deletions(-)

for the vm part this looks fine, the new log lines show up in the log
for a vm's snapshot without ram, but not with ram or backups:

issuing guest-agent 'fs-freeze' command
snapshotting 'drive-scsi0' (vms:vm-100-disk-0)
issuing guest-agent 'fs-thaw' command
TASK OK

for a container this now always says:

freezing guest filesystem
thawing guest filesystem
TASK OK

however, for backups it looks like this:

INFO: starting new backup job: vzdump 101 --remove 0 --mode snapshot --node pve-icon-cleanup --storage local --compress zstd --notification-mode notification-system --notes-template '{{guestname}}'
INFO: Starting Backup of VM 101 (lxc)
INFO: Backup started at 2025-09-01 14:54:33
INFO: status = running
INFO: CT Name: CT101
INFO: including mount point rootfs ('/') in backup
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: create storage snapshot 'vzdump'
freezing guest filesystem
thawing guest filesystem
INFO: creating vzdump archive '/var/lib/vz/dump/vzdump-lxc-101-2025_09_01-14_54_33.tar.zst'
INFO: Total bytes written: 697968640 (666MiB, 215MiB/s)
INFO: archive file size: 201MB
INFO: adding notes to backup
INFO: cleanup temporary 'vzdump' snapshot
INFO: Finished Backup of VM 101 (00:00:03)
INFO: Backup finished at 2025-09-01 14:54:36
INFO: Backup job finished successfully
INFO: notified via target `mail-to-root`
TASK OK

imo it would be nicer to pass down the log function so that it can log
those two lines with the proper log level (`INFO`) here too. however, i
am not sure if that is particularly useful for containers in general. we
don't expose a setting for turning freezing/thawing here to users. the
mechanism is different in my understanding too, as we don't need to rely
on a guest agent for containers anyway. possibly the patch for
pve-container can just be dropped?

other than that:

Tested-by: Shannon Sterz <s.sterz at proxmox.com>
Reviewed-by: Shannon Sterz <s.sterz at proxmox.com>