Proxmox VE 5.4 Multiple NFS Storage and Slow Backup


Oct 2, 2019
Hi All,

We have a very odd issue. With one NFS Data Store mounted our environment works as expected, with fast backups. Example VM which has a 300GB hard drive backs up within 2 hours 45 minutes. However when we mount the 2nd NFS Data Store the backup time increases to 3 hours 20 minutes - you can see read / write speed drop and then gets slower each day so within 7 days it has increased the backup time to over 7 hours. Remove the data store and the backup returns to normal.

Here are the 2 mounts :-

Thecus NAS
x.x.10.12:/raid0/data/_NAS_NFS_Exports_/pve-backup on /mnt/pve/NAS07-NFS type nfs (rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=x.x.10.12,mountvers=3,mountport=58544,mountproto=udp,local_lock=none,addr=x.x.10.12)

x.x.11.11:/pve-storage on /mnt/pve/NAS06-NFS type nfs (rw,relatime,vers=3,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=x.x.11.11,mountvers=3,mountport=30000,mountproto=udp,local_lock=none,addr=x.x.11.11)

Connected by separate 10GB ethernet directly into Thecus NAS and a QNap NAS.

With either connected on their own it works as expected. Introduce the other and the issue occurs and slowly gets worse. Performance within the VM's seems un-affected it only seems to affect backups.

Thecus only supports NFS 3 where as QNap NFS 3 or 4 - have tried both versions without success.

Any advice greatly appreciated.



whats the backing storage of your vms?
Hi Tim

Exactly the same mounts that are used for backup. There is no noticeable performance decrease in any of the VMs either Windows or Linux based whether the backup is running or not

Hi All,

Just to update this I have tracked the issue down to leaving the web interface to Proxmox open. So if its left open the daily backup slows down on a daily basis as described above. If its closed after use then there are no speed issues. So not related to NFS shares at all but still none the less a pretty odd issue.

This seems to have started happening around September 2019 as before this it did not cause the above mentioned behaviour.



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