Backing up Proxmox Virtual Environment to Synology NAS

This article goes trough setting up NFS connection between Synology and PVE Database. Although using Proxmox Backup Server is better for keeping more backups using deduplication, verification and pruning options, having additional backup job directly from PVE instance can increase redundancy in case of PBS failure.
Having Proxmox Virtual Environment and Synology NAS up and running are pre requisite for this setup.
Setting up NFS connection on Synology
Open the Control Panel on Synology DSM and select File Services then NFS
Select Enable NFS service and then Apply. (NFSv3 is still a safe, but selecting latest protocol is always a good idea)
Select Shared Folder in Control Panel, then Create new or Edit the folder where you’d like your Proxmox data to be stored
Select NFS Permissions
IP: put the IP address of Proxmox machine
Privilege: Leave it Read/Write so pve can access backups when needed
Squash: Set to No Mapping
Select Allow users to access mounted subfolders
Click Save
Make sure Synology Firewall is configured to allow Proxmox IP address to access Synology via NFS. Also, on Unifi router settings ensure that there is a rule set to allow access.
Proxmox  Storage Configuration
Login to Proxmox Virtual Environment
Select Datacenter then Storage
Select Add then NFS
At the NFS screen
Create an ID
IP Address of your Synology NAS server
In the Export drop-down menu, the location of your Proxmox folder should automatically appear (If not, there is problem with Synology Firewall or Router Firewall)
In the Content drop-down, select ALL entries. You can then select Add
Proxmox should now show the Synology NAS Storage that we created above
Setting up Backup Job
We can now backup individual machines or create a backup job
Under Datacenter go to Backups
Select Add button
In Backup Job window under General
Keep Node to All
Storage: Select NFS storage we configured
Schedule: Pick date that works best for you
Selection Mode: Either select all or manually choose which VMs and LXCs to run backup for
Mode: Snapshot for daily backup, Suspend or Stop for weekly (make sure that your applications are set to automatically start at reboot)
In Backup Job window under Retention
Set retention that best works for you, depending on the storage size allocated