ExternalUSB+LUKS+LVM

Format the drive for encryption, supply pass or key..

# cryptsetup luksFormat /dev/sdb

Open and mount the drive, it will be available at /dev/mapper/external

# cryptsetup luksOpen /dev/sdb external

Create LVM (PV, VG, LV), format as ext4 reserving 0% for root, and mount the drive.

# pvcreate /dev/mapper/external
# vgcreate vg-backup /dev/mapper/external
# lvcreate -l 17884 vg-backup
# mkfs.ext4 -m 0 /dev/vg-backup/lvol0
# mount /dev/vg-backup/lvol0 /mnt/backup

To unmount;

# umount /mnt/backup
# lvchange -a n /dev/vg-backup/lvol0
# vgchange -a n vg-backup
# cryptsetup luksClose /dev/mapper/external

To mount;

# cryptsetup luksOpen /dev/sdb
# mount /dev/vg-backup/lvol0 /mnt/backup

Research: What is the best way to remove LVM's left over device files.

Rsync backup; This is a dry run which will delete files not on the source, log everything to ~/backup.log, exclude a video directory from all files named /mnt/raid5 to /mnt/backup.

# rsync -avn --delete --log-file=/root/raid5_backup.log --exclude drew/video /mnt/raid5/ /mnt/backup

The real deal.

# rsync -av --delete --log-file=/root/raid5_backup.log --exclude drew/video /mnt/raid5/ /mnt/backup