backup to nas synology

[titof2375]

Hello, here I would like to make backups of my vms and lxc on my nas synology, except that I cannot make a backup of mex lxc.
here is the error code.

  WARNING: You have not turned on protection against thin pools running out of space.
  WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full.
  Logical volume "snap_vm-104-disk-0_vzdump" created.
  WARNING: Sum of all thin volume sizes (162.00 GiB) exceeds the size of thin pool pve/data and the amount of free space in volume group (16.00 GiB).
INFO: creating vzdump archive '/mnt/pve/Sauvegardes/dump/vzdump-lxc-104-2023_02_25-09_03_52.tar.zst'
INFO: tar: /mnt/pve/Sauvegardes/dump/vzdump-lxc-104-2023_02_25-09_03_52.tmp: Cannot open: Permission denied
INFO: tar: Error is not recoverable: exiting now
INFO: cleanup temporary 'vzdump' snapshot
  Logical volume "snap_vm-104-disk-0_vzdump" successfully removed
ERROR: Backup of VM 104 failed - command 'set -o pipefail && lxc-usernsexec -m u:0:100000:65536 -m g:0:100000:65536 -- tar cpf - --totals --one-file-system -p --sparse --numeric-owner --acls --xattrs '--xattrs-include=user.*' '--xattrs-include=security.capability' '--warning=no-file-ignored' '--warning=no-xattr-write' --one-file-system '--warning=no-file-ignored' '--directory=/mnt/pve/Sauvegardes/dump/vzdump-lxc-104-2023_02_25-09_03_52.tmp' ./etc/vzdump/pct.conf ./etc/vzdump/pct.fw '--directory=/mnt/vzsnap0' --no-anchored '--exclude=lost+found' --anchored '--exclude=./tmp/?*' '--exclude=./var/tmp/?*' '--exclude=./var/run/?*.pid' ./ | zstd --rsyncable '--threads=1' >/mnt/pve/Sauvegardes/dump/vzdump-lxc-104-2023_02_25-09_03_52.tar.dat' failed: exit code 2
INFO: Failed at 2023-02-25 09:03:53
INFO: Backup job finished with errors
TASK ERROR: job errors```

[tteck]

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[towerhand]

That looks like the error I was dealing with recently. I got it for trying to back up unprivileged containers to my NFS storage volume and needed a workaround to fix the user privileges to work with the NFS shared folder on the Synology (At least that was my case). The easiest fix I found was to change the squash settings on the shared folder to "Map all to admin" on the Synology and remount the folder on Proxmox.

[titof2375]

by putting the parameters map on admin