Backup pi-hole to NFS Share automatically via cron

Get Destination NFS mount info

On the machine that is acting as your NFS server run the following to get a list of all NFS shares.
You'll need this later when mounting the NFS share on the client.
exportfs -v

/mnt/user/Backup
                <world>(rw,async,wdelay,hide,no_subtree_check,fsid=102,anonuid=9                                             9,anongid=100,sec=sys,insecure,root_squash,all_squash)

Mount nfs share

First we need to create a mount point for the share.
sudo mkdir /mnt/Backup

Manually

Test manually mounting the NFS share before adding to /etc/fstab
sudo mount -t nfs 192.168.1.10:/mnt/user/Backup/pihole /mnt/Backup/

If that works you should be able to cd /mnt/Backup/ and touch a file.
cd /mnt/Backup && touch test.txt && ls -l

Remove the test.txt file we won't need for anything else.
It was only created to verify write access to the NFS share.
rm -f /mnt/Backup/test.txt

Automatically with /etc/fstab

sudo vi /etc/fstab

192.168.1.10:/mnt/user/Backup/pihole    /mnt/Backup/     nfs    defaults    0    0  

If you didn't manually mount the share in the previous section you need to do that now or reboot.
The mount command will read the contents of /etc/fstab and mount the share.
sudo mount /mnt/Backup

Backup Script (~/pihole_backup.sh)

vi ~/pihole_backup.sh

pihole_backup.sh contents

chmod u+x ~/pihole_backup.sh

Add script to Cron

crontab -e
0 5 * * * ~/pihole_backup.sh