If you are running CentOS7 or RHEL 7 with d3backup. You may want this program to be a service running in the background.
First create the systemd service for d3backup
vi /etc/systemd/system/d3backup.service
[Unit]
Description=d3backup Service
After=network.target
[Service]
Type=simple
User=root
ExecStart=/usr/bin/d3backup -b
Restart=always
[Install]
WantedBy=multi-user.target
Then make systemd to reload and start it
systemctl daemon-reload
systemctl enable d3backup.service
systemctl start d3backup.service