PBS backups drive thats disabled?

[Str1atum]

Hi!

I got a particular setup with a VM that has two attached disks to exclude some files from being backed up.



scsi0 is the OS, scsi1 should be backuped. and scsi2 not.

In the client OS I have created zfs pools to be able to easily enforce some quotas for sub-datastores - one zfs pool for each disk:



In my thinking this should exclude all files on datastore-nobackup from being backuped to PBS.

The disk-2.qcow2 is also not present in the backed up disks as expected:


I did, however, a fresh install of a new PBS instance today and the used space on the backup datastore after one initial backup can only be explained by the size of both disks together (the nobackup is filled with 500+ GB and backup is just around 100 GB - so the difference is obvious).

How can I exclude this disk from being backed up?

Sr1atum

 

[fiona]

Hi,
the disk is not backed-up. But VM backup uses chunks of 4MiB fixed size, which is likely why you can see some overhead in the usage. I.e. if there is a part of the disk that has 1MiB of data, the backup will still back-up a whole chunk of size 4MiB for it. Most file systems will keep data contiguous if possible, so the amplification is usually not too bad.

 

[Str1atum]

I realize that but the initial backup size should be something around 300 GB but is around 700 GB - that can't be explained by the chunk size.
I also tried emptying the datastore-nobackup zpool before re-creating an initial backup and the used disk space was 300 GB then as expected. So somehow the mounted disk / zpool is backed up to PBS.

 

[Str1atum]

Any more ideas on that?
Somehow the zfs data in the "not to backup" disk is backuped still and I am looking for a way to avoid that.

 

[Chris]

Any more ideas on that?
Somehow the zfs data in the "not to backup" disk is backuped still and I am looking for a way to avoid that.

From what stems your conclusion that the "not to backup" disk might be included? How did you check the actual on disk size of the backup snapshots? As you showed above, only disks attached to scsi0 and scsi1 are backed up.

Please share a complete task log for a backup job from the PVE host as well as the corresponding task log from the PBS host. Also, post the output of cat /etc/pve/storage.cfg from the PVE host and the full VM config qm config --current 107.