1. data2 (optional)

vi /etc/fstab
///
#
LABEL=data2             /data2/         auto    defaults,noatime,nodiratime,commit=100,barrier=0,data=writeback 1 2
/data2/rcam/            /data1/rcam/    auto    bind
mkdir -p /data2
mount /data2
mkdir -p /data1/rcam /data2/rcam
mount -a

2. prereqs

source /etc/cid.conf
curl -ns http://${rdsserver}/sharel/bin/inst-httpd | sh
curl -ns http://${rdsserver}/sharel/bin/inst-ftp-server | sh

3. installation

mkdir -p /opt/rcam/{log,tmp}
chmod -R 1777 /opt/rcam/{log,tmp}/
 source /etc/cid.conf
 mkdir -p /data1/rcam/{cap,ftp,rec}
 curl -ns http://${rdsserver}/sharel/bin/inst-rcam | sh -s "install"
# cube /etc/httpd/conf.d/rcam.conf "d01.net" with "$(dnsdomainname)"
# chown -R apache: /data1/rcam/{rec,ftp}/_sfpg_data/
systemctl reload httpd
systemctl enable --now ss-rcam.service

4. cron config

sed -i s~"#\*/1 "~"\*/1 "~ /etc/cron.d/cid-cron
echo "/opt/rcam/bin/rcam-ftp-rename /data1/rcam/ftp/cam061/" >> /bin/cid-cron01
echo "/opt/rcam/bin/rcam-cleanup" >> /bin/cid-daily

5. replace the external disk

systemctl disable --now ss-rcam.service
umount /data1/rcam/
umount /data2/

remove the external disk, install the new disk, (re)partition the disk

Tip if the new disk is larger than 2TB, use gpt 
mkfs.ext4 -m 0.1 -L data2 /dev/sda1
mount /data2
mkdir -p /data1/rcam /data2/rcam/{cap,ftp,rec}
mount -a
chown -R "camusr:camgroup" /data1/rcam/
/opt/rcam/bin/rcam-push
systemctl enable --now ss-rcam.service