Fiona Ebner ... How is Backup Fleecing Going?

[tcabernoch]

Sorry to bug you. There are so many people waiting for this feature.
Can you give us some crumbs?

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See here.
https://lists.proxmox.com/pipermail/pve-devel/2024-January/061470.html

When a backup for a VM is started, QEMU will install a
"copy-before-write" filter in its block layer. This filter ensures
that upon new guest writes, old data still needed for the backup is
sent to the backup target first. The guest write blocks until this
operation is finished so guest IO to not-yet-backed-up sectors will be
limited by the speed of the backup target.

With backup fleecing, such old data is cached in a fleecing image
rather than sent directly to the backup target. This can help guest IO
performance and even prevent hangs in certain scenarios, at the cost
of requiring more storage space.

 

[davemcl]

Its in the just released PVE 8.2

 

[tcabernoch]

That one link is the only bit of actual info I've found.
I'd love to get anything else.
Directions on how to set it up would be lovely, but anything, really.

 

[davemcl]

Under Datacenter view -> backup jobs -> advanced

 

[stv.Bundesadmin]

That one link is the only bit of actual info I've found.
I'd love to get anything else.
Directions on how to set it up would be lovely, but anything, really.

It's actually widely mentioned in all the changelogs ;-)

https://www.proxmox.com/en/about/press-releases/proxmox-virtual-environment-8-2
https://pve.proxmox.com/wiki/Roadmap#Proxmox_VE_8.2

And in the docs, of course:
https://pve.proxmox.com/pve-docs/chapter-vzdump.html#_vm_backup_fleecing

But yes, it's not well described how to set it up at all - only the Roadmap mentions it in one sentence:
Fleecing can be configured for a datacenter-wide backup job in the GUI, and be used through the CLI and API.

The docs generally describe it, but fail to mention where to configure it.
There is a small screenshot showing it in the backup job advanced settings, but no text indicating it!
https://pve.proxmox.com/pve-docs/images/screenshot/gui-cluster-backup-edit-04-advanced.png

that is right next to the last paragraph in https://pve.proxmox.com/pve-docs/chapter-vzdump.html#vzdump_jobs
But while the screenshot was updated for fleecing, the text was not.

There are a few settings for tuning backup performance (some of which are exposed in the Advanced tab in the UI). 
The most notable is bwlimit for limiting IO bandwidth. The amount of threads used for the compressor can be controlled
 with the pigz (replacing gzip), respectively, zstd setting. Furthermore, there are ionice (when the BFQ scheduler is used)
 and, as part of the performance setting, max-workers (affects VM backups only) and pbs-entries-max (affects container
 backups only). See the configuration options for details.

 

[tcabernoch]

And there it is. Thanks! Time for some testing.