NFS configuraton on PBS is not backing up

[faisa7847]

I have a pbs server using a nfs share


Filesystem Size Used Avail Use% Mounted on
udev 953M 0 953M 0% /dev
tmpfs 197M 756K 197M 1% /run
/dev/mapper/pbs-root 29G 2.4G 26G 9% /
tmpfs 985M 0 985M 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
10.145.11.25:/PBSbackups 102T 37T 65T 37% /mnt/datastore/DS01-NFS
tmpfs 197M 0 197M 0% /run/user/0

now when I create the daasotre the datastore see the storage and is using well but running backup on proxmox gives me error




INFO: starting new backup job: vzdump 103 102 --mode snapshot --fleecing 0 --all 0 --node NFPVE02 --compress zstd --notes-template '{{guestname}}' --storage DS01-NFS
INFO: Starting Backup of VM 102 (qemu)
INFO: Backup started at 2025-06-26 00:25:31
INFO: status = running
INFO: VM Name: WAZUH
INFO: include disk 'scsi0' 'local-lvm:vm-102-disk-0' 34304M
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: creating Proxmox Backup Server archive 'vm/102/2025-06-25T22:25:31Z'
ERROR: VM 102 qmp command 'backup' failed - backup connect failed: command error: Input/output error (os error 5)
INFO: aborting backup job
INFO: resuming VM again
ERROR: Backup of VM 102 failed - VM 102 qmp command 'backup' failed - backup connect failed: command error: Input/output error (os error 5)
INFO: Failed at 2025-06-26 00:25:31
INFO: Backup job finished with errors
INFO: notified via target `mail-to-root`
TASK ERROR: job errors


and PBS journal log error


Jun 26 00:24:07 pbs proxmox-backup-proxy[655]: GET //api2/json/backup?backup-id=103&backup-time=1750890247&backup-type=vm&benchmark=false&debug=false&ns=root&store=DS01-NFS: 400 Bad Request: [client [::ffff:172.27.87.6]:47324] Input/output error (os error 5)

 

[Chris]

Hi,
did you already check the NFS system logs for errors? Also, please share your mount parameters obtained from the output of mount | grep DS01-NFS

 

[faisa7847]

i have mounted it on DS02-NFS now still facing the same

10.145.11.25:/PBSbackups on /mnt/datastore/DS02-NFS type nfs (rw,relatime,vers=3,rsize=32768,wsize=32768,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=10.145.11.25,mountvers=3,mountport=2049,mountproto=udp,local_lock=none,addr=10.145.11.25)

 

[Chris]

You might want to use the no_root_squash mount option, see also this thread https://forum.proxmox.com/threads/datastore-on-nfs.144880/post-652660

What is the output of ls -l /mnt/datastore/DS02-NFS?