Backup of Container to Synology Fails

[hval007]

Hi Folks,

My Proxmox [v7.0.8] runs into errors when backing up containers to Synology share via NFS [see logs]. Interestingly VM backups work just fine [see logs].
I have several containers none of them which seem to backup.

I followed this guide on Youtube to setup the NFS share ensuring permissions were correct to shared folder.

The output below from manual backup of a container shows it attempts to backup, I can even see the backup file on Synology increase to approx 800MB before it fails and deletes the backup file.

Any ideas?

Failed Container Backup

Header
Proxmox
Virtual Environment 7.0-8
Search
Container 105 (Ubuntu) on node 'pve'
SynoNFSBackup
Filter VMID
Server View
Logs
()
INFO: starting new backup job: vzdump 105 --storage SynoNFSBackup --remove 0 --node pve --mode snapshot --compress zstd
INFO: Starting Backup of VM 105 (lxc)
INFO: Backup started at 2021-12-05 13:53:30
INFO: status = running
INFO: CT Name: Ubuntu
INFO: including mount point rootfs ('/') in backup
INFO: mode failure - some volumes do not support snapshots
INFO: trying 'suspend' mode instead
INFO: backup mode: suspend
INFO: ionice priority: 7
INFO: CT Name: Ubuntu
INFO: including mount point rootfs ('/') in backup
INFO: temporary directory is on NFS, disabling xattr and acl support, consider configuring a local tmpdir via /etc/vzdump.conf
INFO: starting first sync /proc/2896/root/ to /mnt/pve/SynoNFSBackup/dump/vzdump-lxc-105-2021_12_05-13_53_30.tmp
INFO: first sync finished - transferred 1.21G bytes in 169s
INFO: suspending guest
INFO: starting final sync /proc/2896/root/ to /mnt/pve/SynoNFSBackup/dump/vzdump-lxc-105-2021_12_05-13_53_30.tmp
INFO: final sync finished - transferred 0 bytes in 13s
INFO: resuming guest
INFO: guest is online again after 13 seconds
INFO: creating vzdump archive '/mnt/pve/SynoNFSBackup/dump/vzdump-lxc-105-2021_12_05-13_53_30.tar.zst'
INFO: tar: /mnt/pve/SynoNFSBackup/dump/vzdump-lxc-105-2021_12_05-13_53_30.tmp: Cannot open: Permission denied
INFO: tar: Error is not recoverable: exiting now
ERROR: Backup of VM 105 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/SynoNFSBackup/dump/vzdump-lxc-105-2021_12_05-13_53_30.tmp' ./etc/vzdump/pct.conf ./etc/vzdump/pct.fw '--directory=/mnt/pve/SynoNFSBackup/dump/vzdump-lxc-105-2021_12_05-13_53_30.tmp' --no-anchored '--exclude=lost+found' --anchored '--exclude=./tmp/?*' '--exclude=./var/tmp/?*' '--exclude=./var/run/?*.pid' . | zstd --rsyncable '--threads=1' >/mnt/pve/SynoNFSBackup/dump/vzdump-lxc-105-2021_12_05-13_53_30.tar.dat' failed: exit code 2
INFO: Failed at 2021-12-05 13:57:10
INFO: Backup job finished with errors
TASK ERROR: job errors

Successful VM backup

Header
Proxmox
Virtual Environment 7.0-8
Search
Virtual Machine 102 (Homeassistant) on node 'pve'
SynoNFSBackup
Filter VMID
Server View
Logs
()
INFO: starting new backup job: vzdump 102 --storage SynoNFSBackup --remove 0 --node pve --mode snapshot --compress zstd
INFO: Starting Backup of VM 102 (qemu)
INFO: Backup started at 2021-12-05 14:05:52
INFO: status = running
INFO: VM Name: Homeassistant
INFO: include disk 'scsi0' 'local-lvm:vm-102-disk-2' 32G
INFO: include disk 'efidisk0' 'local-lvm:vm-102-disk-1' 4M
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: creating vzdump archive '/mnt/pve/SynoNFSBackup/dump/vzdump-qemu-102-2021_12_05-14_05_52.vma.zst'
INFO: started backup task '642417c1-db54-4c08-9b97-76f94cab317c'
INFO: resuming VM again
INFO:   1% (478.5 MiB of 32.0 GiB) in 3s, read: 159.5 MiB/s, write: 114.4 MiB/s
INFO:   3% (1.2 GiB of 32.0 GiB) in 6s, read: 267.0 MiB/s, write: 166.1 MiB/s
INFO:   5% (1.7 GiB of 32.0 GiB) in 9s, read: 137.8 MiB/s, write: 136.1 MiB/s
INFO:   6% (2.2 GiB of 32.0 GiB) in 12s, read: 172.8 MiB/s, write: 143.0 MiB/s
INFO:   8% (2.6 GiB of 32.0 GiB) in 15s, read: 154.7 MiB/s, write: 148.4 MiB/s
INFO:   9% (3.1 GiB of 32.0 GiB) in 18s, read: 169.2 MiB/s, write: 122.5 MiB/s
INFO:  11% (3.5 GiB of 32.0 GiB) in 21s, read: 142.6 MiB/s, write: 142.6 MiB/s
INFO:  12% (4.0 GiB of 32.0 GiB) in 24s, read: 175.2 MiB/s, write: 166.1 MiB/s
INFO:  14% (4.5 GiB of 32.0 GiB) in 27s, read: 170.4 MiB/s, write: 161.4 MiB/s
INFO:  15% (5.1 GiB of 32.0 GiB) in 30s, read: 180.0 MiB/s, write: 150.3 MiB/s
INFO:  17% (5.6 GiB of 32.0 GiB) in 33s, read: 169.2 MiB/s, write: 163.7 MiB/s
INFO:  19% (6.1 GiB of 32.0 GiB) in 36s, read: 181.2 MiB/s, write: 179.5 MiB/s
INFO:  20% (6.6 GiB of 32.0 GiB) in 39s, read: 187.3 MiB/s, write: 181.5 MiB/s
INFO:  22% (7.1 GiB of 32.0 GiB) in 42s, read: 142.6 MiB/s, write: 124.5 MiB/s
INFO:  23% (7.5 GiB of 32.0 GiB) in 45s, read: 157.1 MiB/s, write: 153.5 MiB/s
INFO:  25% (8.1 GiB of 32.0 GiB) in 48s, read: 187.0 MiB/s, write: 178.3 MiB/s
INFO:  26% (8.6 GiB of 32.0 GiB) in 51s, read: 193.6 MiB/s, write: 174.8 MiB/s
INFO:  28% (9.2 GiB of 32.0 GiB) in 54s, read: 188.5 MiB/s, write: 158.2 MiB/s
INFO:  30% (9.7 GiB of 32.0 GiB) in 57s, read: 188.5 MiB/s, write: 187.6 MiB/s
INFO:  33% (10.9 GiB of 32.0 GiB) in 1m, read: 387.9 MiB/s, write: 136.4 MiB/s
INFO:  35% (11.3 GiB of 32.0 GiB) in 1m 3s, read: 129.2 MiB/s, write: 125.6 MiB/s
INFO:  36% (11.8 GiB of 32.0 GiB) in 1m 6s, read: 182.5 MiB/s, write: 169.7 MiB/s
INFO:  38% (12.3 GiB of 32.0 GiB) in 1m 9s, read: 164.3 MiB/s, write: 149.6 MiB/s
INFO:  39% (12.7 GiB of 32.0 GiB) in 1m 12s, read: 155.9 MiB/s, write: 138.2 MiB/s
INFO:  41% (13.3 GiB of 32.0 GiB) in 1m 15s, read: 195.8 MiB/s, write: 165.4 MiB/s
INFO:  43% (13.8 GiB of 32.0 GiB) in 1m 18s, read: 177.6 MiB/s, write: 162.1 MiB/s
INFO:  44% (14.4 GiB of 32.0 GiB) in 1m 21s, read: 182.5 MiB/s, write: 162.3 MiB/s
INFO:  46% (15.0 GiB of 32.0 GiB) in 1m 24s, read: 210.2 MiB/s, write: 164.5 MiB/s
INFO:  48% (15.5 GiB of 32.0 GiB) in 1m 27s, read: 168.5 MiB/s, write: 147.7 MiB/s
INFO:  49% (16.0 GiB of 32.0 GiB) in 1m 30s, read: 174.7 MiB/s, write: 158.9 MiB/s
INFO:  51% (16.5 GiB of 32.0 GiB) in 1m 33s, read: 177.6 MiB/s, write: 163.7 MiB/s
INFO:  53% (17.1 GiB of 32.0 GiB) in 1m 36s, read: 218.7 MiB/s, write: 162.2 MiB/s
INFO:  55% (17.7 GiB of 32.0 GiB) in 1m 39s, read: 177.6 MiB/s, write: 161.1 MiB/s
INFO:  56% (18.2 GiB of 32.0 GiB) in 1m 42s, read: 175.2 MiB/s, write: 157.3 MiB/s
INFO:  58% (18.7 GiB of 32.0 GiB) in 1m 45s, read: 181.2 MiB/s, write: 161.0 MiB/s
INFO:  59% (19.1 GiB of 32.0 GiB) in 1m 48s, read: 149.9 MiB/s, write: 118.4 MiB/s
INFO:  61% (19.6 GiB of 32.0 GiB) in 1m 51s, read: 169.2 MiB/s, write: 158.2 MiB/s
INFO:  63% (20.2 GiB of 32.0 GiB) in 1m 54s, read: 184.9 MiB/s, write: 174.5 MiB/s
INFO:  64% (20.7 GiB of 32.0 GiB) in 1m 57s, read: 178.4 MiB/s, write: 158.9 MiB/s
INFO:  66% (21.2 GiB of 32.0 GiB) in 2m, read: 161.1 MiB/s, write: 127.1 MiB/s
INFO:  67% (21.7 GiB of 32.0 GiB) in 2m 3s, read: 189.7 MiB/s, write: 164.3 MiB/s
INFO:  69% (22.3 GiB of 32.0 GiB) in 2m 6s, read: 197.0 MiB/s, write: 172.5 MiB/s
INFO:  71% (22.9 GiB of 32.0 GiB) in 2m 9s, read: 204.2 MiB/s, write: 163.0 MiB/s
INFO:  72% (23.3 GiB of 32.0 GiB) in 2m 12s, read: 131.7 MiB/s, write: 128.1 MiB/s
INFO:  74% (23.9 GiB of 32.0 GiB) in 2m 15s, read: 195.8 MiB/s, write: 175.3 MiB/s
INFO:  76% (24.4 GiB of 32.0 GiB) in 2m 18s, read: 187.3 MiB/s, write: 144.5 MiB/s
INFO:  78% (25.0 GiB of 32.0 GiB) in 2m 21s, read: 216.3 MiB/s, write: 129.2 MiB/s
INFO:  84% (27.0 GiB of 32.0 GiB) in 2m 24s, read: 663.4 MiB/s, write: 121.1 MiB/s
INFO:  85% (27.3 GiB of 32.0 GiB) in 2m 27s, read: 107.5 MiB/s, write: 105.0 MiB/s
INFO:  86% (27.8 GiB of 32.0 GiB) in 2m 30s, read: 178.8 MiB/s, write: 148.7 MiB/s
INFO:  88% (28.4 GiB of 32.0 GiB) in 2m 33s, read: 209.0 MiB/s, write: 205.7 MiB/s
INFO:  90% (29.0 GiB of 32.0 GiB) in 2m 36s, read: 203.0 MiB/s, write: 153.3 MiB/s
INFO:  92% (29.5 GiB of 32.0 GiB) in 2m 39s, read: 160.7 MiB/s, write: 130.2 MiB/s
INFO:  93% (30.0 GiB of 32.0 GiB) in 2m 42s, read: 175.2 MiB/s, write: 120.6 MiB/s
INFO:  95% (30.6 GiB of 32.0 GiB) in 2m 45s, read: 215.1 MiB/s, write: 144.4 MiB/s
INFO:  97% (31.3 GiB of 32.0 GiB) in 2m 48s, read: 228.4 MiB/s, write: 137.5 MiB/s
INFO:  99% (31.8 GiB of 32.0 GiB) in 2m 51s, read: 177.6 MiB/s, write: 119.6 MiB/s
INFO: 100% (32.0 GiB of 32.0 GiB) in 2m 52s, read: 164.9 MiB/s, write: 116.1 MiB/s
INFO: backup is sparse: 6.58 GiB (20%) total zero data
INFO: transferred 32.00 GiB in 172 seconds (190.5 MiB/s)
INFO: archive file size: 7.33GB
INFO: Finished Backup of VM 102 (00:02:56)
INFO: Backup finished at 2021-12-05 14:08:48
INFO: Backup job finished successfully
TASK OK

 

[Dunuin]

There are a dozen of threads about this same problem. So please use the search function. In short:
unprivileged LXCs need the backup folder to be chmod 777 because of the user remapping. Most people just don't manage to get the rights right on the Synology NFS share. Another option would be to set the "tmpdir" variable in the /etc/vzdump.conf to "/tmp" so temporary backups will be written to your local "/tmp" instead which is already set to 777.