fast incremental mode not run when backup mode = stop

[jmjosebest]

Hello,

to move a VPS to another node that is outside a cluster I had thought about this procedure:

- Snapshot backup without shutting down the VPS.
- Shutdown the VPS
- Second backup with the VPS turned off

I thought that this way the second backup would be done faster, but my surprise is that the second backup does not run the "fast incremental mode".

It's normal?

1st Backup

INFO: starting new backup job: vzdump 1503 --node ns1016 --storage pbs --compress zstd
INFO: Starting Backup of VM 1503 (qemu)
INFO: Backup started at 2021-05-17 10:05:04
INFO: status = running
INFO: VM Name: xxx
INFO: include disk 'ide0' 'nvme:1503/vm-1503-disk-0.raw' 50G
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: creating Proxmox Backup Server archive 'vm/1503/2021-05-17T08:05:04Z'
INFO: started backup task '25aa3824-5a46-4c07-ae2f-a3e11701c6e5'
INFO: resuming VM again
INFO: ide0: dirty-bitmap status: OK (836.0 MiB of 50.0 GiB dirty)
INFO: using fast incremental mode (dirty-bitmap), 836.0 MiB dirty of 50.0 GiB total
INFO:  47% (396.0 MiB of 836.0 MiB) in  3s, read: 132.0 MiB/s, write: 129.3 MiB/s
INFO:  92% (776.0 MiB of 836.0 MiB) in  6s, read: 126.7 MiB/s, write: 126.7 MiB/s
INFO: 100% (836.0 MiB of 836.0 MiB) in  7s, read: 60.0 MiB/s, write: 60.0 MiB/s
INFO: backup was done incrementally, reused 49.19 GiB (98%)

2nd Backup

INFO: starting new backup job: vzdump 1503 --node ns1016 --storage pbs --compress zstd
INFO: Starting Backup of VM 1503 (qemu)
INFO: Backup started at 2021-05-17 10:06:07
INFO: status = stopped
INFO: backup mode: stop
INFO: ionice priority: 7
INFO: VM Name: xxx
INFO: include disk 'ide0' 'nvme:1503/vm-1503-disk-0.raw' 50G
INFO: creating Proxmox Backup Server archive 'vm/1503/2021-05-17T08:06:07Z'
INFO: starting kvm to execute backup task
INFO: started backup task '43b4fa91-d0e3-404b-9b41-d24d85f3ee15'
INFO: ide0: dirty-bitmap status: created new
INFO:   1% (952.0 MiB of 50.0 GiB) in  3s, read: 317.3 MiB/s, write: 1.3 MiB/s
INFO:   3% (1.7 GiB of 50.0 GiB) in  6s, read: 272.0 MiB/s, write: 1.3 MiB/s
INFO:   5% (2.5 GiB of 50.0 GiB) in  9s, read: 270.7 MiB/s, write: 0 B/s
INFO:   6% (3.3 GiB of 50.0 GiB) in 12s, read: 276.0 MiB/s, write: 0 B/s
INFO:   8% (4.1 GiB of 50.0 GiB) in 15s, read: 262.7 MiB/s, write: 16.0 MiB/s
INFO:   9% (4.9 GiB of 50.0 GiB) in 18s, read: 281.3 MiB/s, write: 0 B/s
INFO:  11% (5.7 GiB of 50.0 GiB) in 21s, read: 277.3 MiB/s, write: 2.7 MiB/s
INFO:  13% (6.5 GiB of 50.0 GiB) in 24s, read: 274.7 MiB/s, write: 0 B/s
INFO:  14% (7.3 GiB of 50.0 GiB) in 27s, read: 272.0 MiB/s, write: 0 B/s
INFO:  16% (8.1 GiB of 50.0 GiB) in 30s, read: 266.7 MiB/s, write: 1.3 MiB/s

 

[dcsapak]

yes this is expected, the dirty-bitmap that is necessary for the fast-incremental version, is only available (atm) for running vms (and gets discarded on shutdown)