Optimal zvol volblocksize for PBS virtual machine datastores on PVE ZFS storage?

[jaylik]

What is most optimal volblocksize for PBS virtual machine on PVE ZFS storage?

 

[janssensm]

Hi,
You can get some technical details on the creation of the chunks that PBS uses [1]
Also @t.lamprecht posted some guidance [2]

With this info I did some tests for my own (small and cheap) system where I run PBS as a VM on PVE with ZFS.
I ended up with 2 virtual disks on seperate zfs filesystems with their own volblocksize:
Disk for container backups: 64k
Disk for vm backups: 128k

Underlying storage for this PVE host is a ZFS mirror of 2 spinners with 2 small enterprise ssd's as mirror special device.


[1] https://pbs.proxmox.com/docs/technical-overview.html#chunks
[2] https://forum.proxmox.com/threads/backup-repo-zfs-record-size-considerations.73512/post-328175