Increase performance of Proxmox Backups to NFS Targets

I’m using a Proxmox Server at home to virtualize different services. The daily backups are created on an NFS share of my NAS.

While the NFS share usually performs with ~70MB/s, the proxmox backup speed was only around 2MB/s. Backups to the local SSD were finished with ~100MB/s without compression and ~15MB/s with gzip, so it should not be a CPU issue.

There are some threads in the Proxmox Forum about the influence of NFS mount-options and other stuff but in the end the following change workes for me:

If you use the Suspend backup option (see: Backup and Restore - Proxmox VE), Proxmox rsyncs your local OpenVZ folder to the NFS target and zips it afterwards. As the OpenVZ folder contains many many small files, this takes quiet a long time. But you can configure a custom temp-directory for backups inside the vzdump.conf which is used for the rsync process.

tmpdir: /tmp

Now only the large gzip file will be transferred to your NFS share and not every small file. Just keep in mind that you will need some more free space on your local disk.