Stefan,

Watch for duplicate COW setups. If client selected QCOW VM storage on top
of ZFS, that would be a copy on write filesystem on top of another copy on
write filesystem.

Robert Gerber
402-237-8692
[email protected]

On Wed, Apr 29, 2026, 8:22 AM Stefan G. Weichinger via Bacula-users <
[email protected]> wrote:

> Am 29.04.26 um 14:39 schrieb Heitor Faria:
> > Hello Stefan,
> >
> >     Things work, but I only see around 50-70 MB/s for backups.
> >
> > You obviously have a bottleneck. You need to start measuring: network
> > (iperf); disk writes, reads, your tree walk (e.g. time find /your/path -
> > type f > /dev/null) etc.
>
> I replaced the virtual disk controller in the client from virtio to scsi.
>
> And enabled SSD emulation for that disk.
>
> Changed little ... the disk is read with around 70 MB/s according to
> atop -> shown as "busy 80%" (with virtio it was even higher).
>
> I also checked the mount options for things like "noatime" (ext4).
>
> SSD Emulation might be wrong:
>
> I didn't configure that server, so I just found that the larger
> datastore consists of HDDs: 4x Seagate Exos 28 TB in some kind of ZFS
> pool (!) with raidz2, as far as I see.
>
> hm, this might be the reason for some unwanted overhead here.
>
> Let me repeat: not my idea, not my setup ;-)
>
> > By coincidence, I just published my personal Proxmox Backup Plugin for
> > Bacula Community, which supports the latest Proxmox Backup APIs and
> > provides all PBS functions too: https://www.linkedin.com/posts/
> > heitorbacula_podheitor-plugin-de-backup-replica%C3%A7%C3%A3o-
> > activity-7455206154382782464-6GS_?
> >
> utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAACcSp4BYjaTUSVxav5iossfBRxcPrLdSJM
> <
> https://www.linkedin.com/posts/heitorbacula_podheitor-plugin-de-backup-replica%C3%A7%C3%A3o-activity-7455206154382782464-6GS_?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAACcSp4BYjaTUSVxav5iossfBRxcPrLdSJM
> >
> > PVT if you want to test it.
>
> thanks, not right now.
>
>
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