Don't risk it. Second disk it!
Snapshots are simply an archive of important files. They are organized together by a $NAMESPACE usually derived from the service they follow. If stored on a second disk these may serve as valuable backups for recovering broken services.
Create a folder in $XDG_DATA_DIRS to house snapshot archives. Then create a snapshot system group, make it the owner and give group members write access to the directory.
mkdir -p /usr/local/share/snapshots groupadd --system snapshot chown root:snapshot /usr/local/share/snapshots chmod g+w /usr/local/share/snapshots
Users wishing to create snapshots should be added to this new system group.
usermod -G snapshot -a $USER
Snapshot scripts should be created as /usr/local/bin/$NAMESPACE-snapshot.sh. They should collect their specifically important data into /tmp/snapshot/$NAMESPACE and then create a date-stamped tarball in /usr/local/share/snapshots.
tar -czvf /usr/local/share/snapshots/$(date +%F)-$NAMESPACE.tar.gz -C /tmp/snapshot/$NAMESPACE .
Snapshot implementations should be configured as a systemd.service(5)...
systemctl edit $NAMESPACE-snapshot.service:
[Unit] Description=Snapshot $NAMESPACE [Service] User=$USER Group=snapshot ExecStart=/usr/local/bin/$NAMESPACE-snapshot.sh
...and run regularly by a systemd.timer(5).
systemctl edit $NAMESPACE-snapshot.timer
[Unit] Description=Regularly snapshot $NAMESPACE [Timer] OnBootSec=0min OnCalendar=*-*-* Unit=$NAMESPACE-snapshot.service