Backup error

[Stives]

Hi,

This is the message I get when I make a backup of an LXC Node-red; at the NAS level, I gave the same rights (LXC IP address and DNS) as for my Home Assistant VM for which the backup works?

2024-03-21 16:12:58 INFO: Starting Backup of VM 103 (lxc)
2024-03-21 16:12:58 INFO: status = running
2024-03-21 16:12:58 INFO: CT Name: node-red
2024-03-21 16:12:58 INFO: including mount point rootfs ('/') in backup
2024-03-21 16:12:58 INFO: backup mode: snapshot
2024-03-21 16:12:58 INFO: ionice priority: 7
2024-03-21 16:12:58 INFO: create storage snapshot 'vzdump'
2024-03-21 16:12:58 INFO: creating vzdump archive '/mnt/pve/Svg_VM_Syno/dump/vzdump-lxc-103-2024_03_21-16_12_57.tar.zst'
2024-03-21 16:12:58 INFO: tar: /mnt/pve/Svg_VM_Syno/dump/vzdump-lxc-103-2024_03_21-16_12_57.tmp: Cannot open: Permission denied
2024-03-21 16:12:58 INFO: tar: Error is not recoverable: exiting now
2024-03-21 16:12:58 INFO: cleanup temporary 'vzdump' snapshot
2024-03-21 16:12:59 ERROR: Backup of VM 103 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/Svg_VM_Syno/dump/vzdump-lxc-103-2024_03_21-16_12_57.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/Svg_VM_Syno/dump/vzdump-lxc-103-2024_03_21-16_12_57.tar.dat' failed: exit code 2

 

[Dunuin]

For VMs and privileged LXCs only UID 0 needs write access to the backup storage.
For unprivileged LXCs UID 0 + 100000 are needed.
So either make sure UID 100000 got write access too or edit your /etc/vzdump.conf and set the "tmpdir" to some local folder where UID 0 + 100000 are allowed to write (like "/tmp").

 

[Stives]

Thank you for the answer. How do I translate this to my NAS?

 

[Dunuin]

Thank you for the answer. How do I translate this to my NAS?

Only you know that. Set up your NAS to allow writes from user with UID 0 and 100000 or ignore your NAS and edit your vzdump.conf.

 

[Stives]

Thanks for the vzdump.conf track

I finally used this solution; it will perhaps benefit others:
1) Connect via SSH to Proxmox (with MobaXtherm)
2) Create a temporary folder with the command mkdir /var/lib/vz/tmpdump
3) Edit the /etc/vzdump.conf file (possible directly with the MobaXtherm browser)
4) Uncomment the #tmpdir DIR line and add the path to the temporary folder; the line therefore becomes tmpdir: /var/lib/vz/tmpdump

All backups will go through the /tmpdump folder before being moved to the local or remote backup storage configured in Proxmox
No need to stop the lxc to perform the backup.