vzdump mode stop

_Lars_

Well-Known Member
Jan 11, 2012
45
2
48
I'm a little bit confused about the terminology used with the tools qm and vzdump. qm uses "stop" for hard killing a virtual machine and "shutdown" for sending a graceful ACPI-Event.
Now what is vzdump doing when it is used with '-mode stop'? The manpage says "It works by executing an orderly shutdown of the VM". Does this mean, it behaves like "qm shutdown"?
I only like to be shure... ;-)

EDIT:
Ok, it works like expected. In the past with proxmox 2.3 I did the backup myself with
qm stop <vmid>
vzdump ...
qm start <vmid>
Now I'm trying the included backup scheduler:

-----[backup log]-----
Aug 29 22:59:02 INFO: Starting Backup of VM 104 (qemu)
Aug 29 22:59:02 INFO: status = running
Aug 29 22:59:03 INFO: update VM 104: -lock backup
Aug 29 22:59:03 INFO: backup mode: stop
Aug 29 22:59:03 INFO: ionice priority: 7
Aug 29 22:59:03 INFO: VM Name: testvm001
Aug 29 22:59:03 INFO: include disk 'scsi0' 'lvm_sata:vm-104-disk-1' 80G
Aug 29 22:59:03 INFO: include disk 'scsi1' 'lvm_nvme:vm-104-disk-1' 48G
Aug 29 22:59:04 INFO: stopping vm
Aug 29 22:59:11 INFO: creating archive '/mnt/pve/backup01/dump/vzdump-qemu-104-2017_08_29-22_59_01.vma.lzo'
Aug 29 22:59:11 INFO: starting kvm to execute backup task
Aug 29 22:59:13 INFO: started backup task '30c4fcda-a183-47d2-ab9d-9bebbf7bb6e5'
Aug 29 22:59:13 INFO: resume VM
Aug 29 22:59:16 INFO: status: 0% (503447552/137438953472), sparse 0% (103399424), duration 3, 167/133 MB/s
[...]
Aug 29 23:08:49 INFO: status: 100% (137438953472/137438953472), sparse 80% (110938112000), duration 576, 593/0 MB/s
Aug 29 23:08:49 INFO: transferred 137438 MB in 576 seconds (238 MB/s)
Aug 29 23:08:49 INFO: archive file size: 13.11GB
Aug 29 23:08:50 INFO: vm is online again after 586 seconds
Aug 29 23:08:50 INFO: Finished Backup of VM 104 (00:09:49)
-----[backup log]-----

When all my disks used by the vm are logical volumes the vzdump process makes use of snapshots so that the vm is immediatedly available again after the shutdown and the backup run "in background"? Right?
 
Last edited:
Now what is vzdump doing when it is used with '-mode stop'? The manpage says "It works by executing an orderly shutdown of the VM". Does this mean, it behaves like "qm shutdown"?

yes

When all my disks used by the vm are logical volumes the vzdump process makes use of snapshots so that the vm is immediatedly available again after the shutdown and the backup run "in background"? Right?

yes
 
Thanks Dietmar.

Just for me (backup for vms that only use lvm disks with 'mode stop'):

1) send ACPI-Shutdown to vm
2) wait at least "-stopwait" until the vm is stopped
3) take lvm snapshot
4) restart the vm
5) backing up the disk from snapshot
6) freeing snapshot

Is this correct?
 
No, there are no lvm snapshots involved. Instead, this uses a special qemu feature to provide snapshot semantics.
 

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