Re: [pve-devel] VM Incremental backup for 3-party solution (Qemu)

[Stefan Reiter <s.reiter@proxmox.com>]

On 8/19/21 3:21 PM, Radosław Korzeniewski wrote:
> Hello,
> 
> I'm working on implementing VM incremental backup for a 3-party solution
> based on Qemu dirty bitmap which is available in Proxmox. Unfortunately I'm
> unable to make it working, so I decided to ask for some help.
> First I'm adding a dirty bitmap using the `block-dirty-bitmap-add` command
> and making a full backup with `drive-backup` command.
> Both are executed in transactions. The bitmap is successfully added.
> But the external backup file is populated with ~193K of data and hung.
> The backup job is added and QMP returns 3 events:
> `"status": "created"`, `"status": "running"`, `"status": "paused"`.
> I'm not sure why.
> As finally the job is "paused", I try to resume it with `block-job-resume`
> command
> the `query-block-jobs` returns `"status": "paused"` i `"paused": true`.
> All I can do is to cancel the job with the `block-job-cancel` command.
> No commands return any error.
> 
> Do you have any idea why the job fell into a paused state and how I
> should proceed?
> 

Hi,

as a shot in the dark I would say you specified the bitmap in your initial
backup command, and it only backed up what had been written between the
time you did 'bitmap-add' and 'drive-backup'..

But more importantly, 'drive-backup' and the bitmap support around that
are not based on our code, they are from upstream QEMU. We implement the
'backup' and 'query-backup' QMP calls.

There's nothing against using the native calls if they fit your use case,
but for support it would make more sense to contact upstream and read
through their documentation :)

~ Stefan