Backup of CT fails, VM works

[Morphy8]

Hello,

I am stalling progress on fixing a CT Backup. (Actually I am on the way to move to bigger SSD on my NUC and want to port everything over.

I have a VM running IOBroker and a CT with Portainer for Grafana and Influx.
Backup is to Synology NAS - NFS.

THis works well for the VM but for the CT I have serious issues. Backing up to the NAS is giving me this permission error:

()
{{guestname}}
INFO: starting new backup job: vzdump 200 --storage Diskstation --notes-template '{{guestname}}' --node Proxmox --remove 0 --mode snapshot --compress zstd
INFO: Starting Backup of VM 200 (lxc)
INFO: Backup started at 2023-11-03 16:33:10
INFO: status = running
INFO: CT Name: Docker
INFO: including mount point rootfs ('/') in backup
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: create storage snapshot 'vzdump'
  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-200-disk-0_vzdump" created.
  WARNING: Sum of all thin volume sizes (90.00 GiB) exceeds the size of thin pool pve/data and the size of whole volume group (55.39 GiB).
INFO: creating vzdump archive '/mnt/pve/Diskstation/dump/vzdump-lxc-200-2023_11_03-16_33_10.tar.zst'
INFO: tar: /mnt/pve/Diskstation/dump/vzdump-lxc-200-2023_11_03-16_33_10.tmp: Cannot open: Permission denied
INFO: tar: Error is not recoverable: exiting now
INFO: cleanup temporary 'vzdump' snapshot
  Logical volume "snap_vm-200-disk-0_vzdump" successfully removed
ERROR: Backup of VM 200 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/Diskstation/dump/vzdump-lxc-200-2023_11_03-16_33_10.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/Diskstation/dump/vzdump-lxc-200-2023_11_03-16_33_10.tar.dat' failed: exit code 2
INFO: Failed at 2023-11-03 16:33:11
INFO: Backup job finished with errors
TASK ERROR: job errors

I tried to backup to a FLASH drive directly at the NUC, but this did not work either - it actually did access the drive, but writing did not work somehow:

INFO: starting new backup job: vzdump 200 --storage USB-drive --notes-template '{{guestname}}' --node Proxmox --remove 0 --compress 0 --mode snapshot
INFO: filesystem type on dumpdir is 'devtmpfs' -using /var/tmp/vzdumptmp10242_200 for temporary files
INFO: Starting Backup of VM 200 (lxc)
INFO: Backup started at 2023-11-03 16:22:26
INFO: status = running
INFO: CT Name: Docker
INFO: including mount point rootfs ('/') in backup
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: create storage snapshot 'vzdump'
  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-200-disk-0_vzdump" created.
  WARNING: Sum of all thin volume sizes (90.00 GiB) exceeds the size of thin pool pve/data and the size of whole volume group (55.39 GiB).
INFO: creating vzdump archive '/dev/usb-drive/dump/vzdump-lxc-200-2023_11_03-16_22_26.tar'
INFO: Total bytes written: 8274094080 (7.8GiB, ?/s)
INFO: tar: -: Wrote only 6144 of 10240 bytes
INFO: tar: Error is not recoverable: exiting now
INFO: cleanup temporary 'vzdump' snapshot
  Logical volume "snap_vm-200-disk-0_vzdump" successfully removed
ERROR: Backup of VM 200 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=/var/tmp/vzdumptmp10242_200' ./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' ./ >/dev/usb-drive/dump/vzdump-lxc-200-2023_11_03-16_22_26.dat' failed: exit code 2
INFO: Failed at 2023-11-03 16:23:56
INFO: Backup job finished with errors
TASK ERROR: job errors

I also tried the other way - use Clonezilla to move to bigger SSD, but this tool also did not like my files and stopped executing.
BTW: the CT works flawlessly.

Not sure if backing up is somehow locked up because my file system is totally overcomitted to CT and VM... !? This is the issue I am targeting to resolve.


Thank you for any hint!!!
Morphy

 

[Dunuin]

Please use the forums search function. This was asked and solved uncountable times.

In short:
To back up unprivileged LXC the temporary storage (which defaults to a subdir of your target backup storage) both UID 0 and UID 100000 need write permissions. So either make sure UID 100000 on your NAS also got the rights to write to the share or edit your /etc/vzdump.conf and point the tmpdir to a folder with enough rights like "/tmp" which got 777.

 

[Morphy8]

Apologies - Yes I was not doing the proper search before. I make sure I do next time.
I edited /etc/vzdump.conf and pointed to "/TMP" and it runs nicely - tank you @Dunuin to help anyhow thats a nice gesture.