[PVE-User] Guest-agent fs-freeze command breaks the system

[Amin Vakil]

Tonight one of vms which I backup weekly broke when proxmox issues
guest-agent 'fs-freeze' command.

I could ping the server, but nothing works (almost every port were down,
the remaining didn't respond to anything and I couldn't ssh to it).

Although I haven't faced this issue in three years using proxmox and
last three month enabling and installing qemu-guest-agent on host and
vm, I waited for 20 minutes and nothing happens, then I stopped the
backup, logged in to host and entered

qm unlock 201 && qm reset 201

(201 is VMID of broken vm)

Then when vm gets booted I edited grub command line and add this to the
end (just to be sure filesystem hasn't corrupted):

fsck.mode=force fsck.repair=yes

When the server was booting up lots of errors were getting fixed, errors
were like this:

[  170.013464] systemd-fsck[639]: Free blocks count wrong for group
#2160 (23153, counted=23948).
[  170.014860] systemd-fsck[639]: Fix? yes

and this

[  170.142921] systemd-fsck[639]: Directories count wrong for group
#2000 (1394, counted=871).
[  170.145106] systemd-fsck[639]: Fix? yes

Then the server boots up and everything was fine.

I ran a manual backup again and the same problem happens, everything
freezes when backup reaches guest-agent 'fs-freeze' command and I
couldn't do anything expect unlock and forcefully reset the vm.

Server is updated CentOS 7 (2003) with cPanel installed on it.

I don't know if this helps or not, but the vm has three hard disks, only
backup of the first one which OS is installed on it, is enabled. First
hard disk is in "sas" directory and backup gets written to another
directory "sata".

Also log of first scheduled backup is here (manual backup error log is
exactly the same):

INFO: Starting Backup of VM 201 (qemu)
INFO: Backup started at 2020-05-09 02:00:58
INFO: status = running
INFO: VM Name: ircpanel1
INFO: include disk 'virtio0' 'sas:201/vm-201-disk-0.qcow2' 80G
INFO: exclude disk 'virtio1' 'sata:201/vm-201-disk-0.qcow2' (backup=no)
INFO: exclude disk 'virtio2' 'sata:201/vm-201-disk-1.qcow2' (backup=no)
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: creating archive
'/mnt/pve/sata/dump/vzdump-qemu-201-2020_05_09-02_00_58.vma.lzo'
INFO: issuing guest-agent 'fs-freeze' command
closing with read buffer at /usr/share/perl5/IO/Multiplex.pm line 927.
ERROR: interrupted by signal
INFO: issuing guest-agent 'fs-thaw' command
TASK ERROR: got unexpected control message:

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
URL: <http://lists.proxmox.com/pipermail/pve-user/attachments/20200509/f1278138/attachment.sig>