Where are my backups getting stored?

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hspindel

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Aug 6, 2025
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I am new to this, so possibly making a rookie mistake.

I set up PBS with two datastores. The first datastore is on a USB disk directly attached to the machine running PBS. The second datastore is on a Synology networked share.

On PVE, I set up storage for both the PBS datastores. The USB datastore works perfectly. I can run backups from PVE, the dialog box says the backup completes, and I can view the backed up files either from PVE or from PBS. Both datastores are setup of type Proxmox Backup Server.

On PVE, if I try to run a backup with the destination of the Synology network share, the dialog box says the backup completes. It even verifies. I can view the backed up files from either PVE or from PBS. However, nothing is getting stored on the Synology network share. The only thing I see on the network share is that a subfolder named "dump" is created. And if I delete that folder, it is recreated. There is nothing in the "dump" folder.

So where are the datafiles from the backup to the network share going? If I investigate (using PVE) doing a File Restore from either of backup datastores, I can see the expected files. So they are stored somewhere!
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When I created the datastore in PBS, the field for Backing Path was entered as //SynologyShareName/SynologySharePath. SInce the file named "dump" was created there, PBS understood the path as far as creating a place for the backup files, but no backup files ever appear there.

Thank you for any pointers.

BTW, as a test I also tried setting up a datastore on PVE that points directly to the network share (type SMB/CIFS). If I run backups with that target, the expected backup files do appear on the network share. I would be okay with that as a solution, except I do not see how to enable things like verification and pruning if I bypass PBS.

As further info, I tried systemctl status proxmox-backup and proxmox-backup-proxy. The former complains about not being able to get SMART data from the USB drive, but the USB drive works (perhaps it doesn't support SMART - it's pretty old). The latter gives me this:

Code: 
 proxmox-backup-proxy.service - Proxmox Backup API Proxy Server
     Loaded: loaded (/lib/systemd/system/proxmox-backup-proxy.service; enabled; preset: enabled)
     Active: active (running) since Sun 2025-08-03 15:15:55 PDT; 5 days ago
    Process: 41018 ExecReload=/bin/kill -HUP $MAINPID (code=exited, status=0/SUCCESS)
   Main PID: 41027 (proxmox-backup-)
      Tasks: 10 (limit: 18973)
     Memory: 5.2G
        CPU: 2h 51min 39.805s
     CGroup: /system.slice/proxmox-backup-proxy.service
             └─41027 /usr/lib/x86_64-linux-gnu/proxmox-backup/proxmox-backup-proxy

Aug 08 16:10:01 pbs proxmox-backup-proxy[41027]: [398B blob data]
Aug 08 16:10:18 pbs proxmox-backup-proxy[41027]: [398B blob data]
Aug 08 16:10:36 pbs proxmox-backup-proxy[41027]: [398B blob data]
Aug 08 16:10:56 pbs proxmox-backup-proxy[41027]: [398B blob data]
Aug 08 16:11:07 pbs proxmox-backup-proxy[41027]: [398B blob data]
Aug 08 16:12:55 pbs proxmox-backup-proxy[41027]: error during snapshot file listing: 'unable to load blob '"//DS1522/pbs-replication/vm/103/2025-08-08T2>
Aug 08 16:13:12 pbs proxmox-backup-proxy[41027]: Upload backup log to datastore 'PBS-Storage2', root namespace vm/103/2025-08-08T23:08:37Z/client.log.bl>
Aug 08 16:13:13 pbs proxmox-backup-proxy[41027]: starting new backup on datastore 'PBS-Storage2' from ::ffff:192.1.1.30: "vm/104/2025-08-08T23:13:12Z"
Aug 08 16:17:55 pbs proxmox-backup-proxy[41027]: Upload backup log to datastore 'PBS-Storage2', root namespace vm/104/2025-08-08T23:13:12Z/client.log.bl>
Aug 08 16:28:51 pbs proxmox-backup-proxy[41027]: rrd journal successfully committed (41 files in 0.008 seconds)

PBS-Storage2 is the name of the datastore that I configured to use the Synology network share. You can see in the above that a log was uploaded. But I see nothing uploaded to the actual network location.
 
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Update: the dump directory was being created by a different install of PVE, which I had configured to backup directly to the NAS bypassing PBS. So that's a red herring.

Still need to figure out why I can't configure PVE to backup to the NAS going through PBS.
 
Note that most files generated by PBS - and especially those containing the actual data - are "invisible"/"hidden", the data is in the ".chunks"-folder.
 
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And PBS must have write permission with his user und group IDs
 
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Thank you for your replies. Documenting how I finally got this to work in case anyone else is reading.

Apparently you cannot create a datastore in PBS that points directly to a network share. At least, I couldn't get it to work. What worked was to mount the network share on PBS and point the datastore to the mountpoint.

There were some special incantations for the mount command:

mount -t cifs /serverIP/shareName /mnt/mountpoint -o uid=34,noforceuid,gid=34,noforcegid

I actually have no idea what those options do. I just found them recommended in a post somewhere and gave them a try and they worked.

N

Thread 'Using CIFS/NFS as datastore'

Firsty, so pleased about the news about this product. Probably one of the biggest improvement you could make for Proxmox.

So I got the PBS setup, but since my current backup data are on my NAS, I would like to add it as CIFS/NFS share.
But when I create datastore pointing to /mnt/pvebackup it times out and doesnt work. I tried to check what permission the local datastore used, and from what I could see, it should just be user: backup and group: backup?
post on 7/11/2020 by t.lamprecht

That post mentions that the magic "34" in the mount command is found using the command "id backup". When I ran it on my machine, it also showed 34. Don't know if that's an automatic standard with PBS.
 
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