Why doesn't Proxmox VM backup work?

Question

Proxmox

Good time. There is a Proxmox 5.3-6 hypervisor, it has two zfs pools, local-pool(HDD) and ssd-pool(SSD) . There is a virtual machine with Windows Server 2016 VM 101. Disk C: of this machine is located on ssd-pool, disk D: on hdd-pool, respectively. Snapshots are made without problems. I'm trying to make a backup, I select VM -> Backup -> Run:
Storage - Local (Directory - /var / lib / vz., Content - ISO image, Backup, Container Template,)
Mode - Snapshot / Pause / Stop (tried all)
Compression - LZO / GZIP (tried everything)
Gives an error:
INFO: starting new backup job: vzdump 101 --node pvehost --storage local --compress gzip --remove 0 --mode stop
INFO: Starting Backup of VM 101 (qemu)
INFO: status = running
INFO: update VM 101: -lock backup
INFO: backup mode: stop
INFO: ionice priority: 7
INFO: VM Name: termsrv
ERROR: Backup of VM 101 failed - disk 'virtio0' 'ssd-pool:vm-101-disk- 0' (iothread=on) can't use backup feature currently. Please set backup=no for this drive at /usr/share/perl5/PVE/VZDump/QemuServer.pm line 77.
INFO: Backup job finished with errors
TASK ERROR: job
errors
The Qemu agent on Windows Server is installed.
PS
By googling, I found this https://forum.proxmox.com/threads/backup-failed.28530/
Apparently, backup will not work with the iothread option enabled.

Answer 1

This is an old bug https://bugzilla.proxmox.com/show_bug.cgi?id=1071