As already stated LUKS and mdadm are a good combination. I too use these in all my recent systems. I Create RAID volumes, then LVM, then cryptsetup:
=========
+ mdamd +
+ | +
+ LVM +
+ | +
+ LUKS +
+ | +
+ ext4 +
=========
I can't speak to your system being on USB, but in general you can just do something like the following:
$mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda /dev/sdb
$mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sdc /dev/sdd
$mdadm --create /dev/md2 --level=1 --raid-devices=2 /dev/sde /dev/sdf
If you want to use LVM then you create the PV, VG, and LV:
$pvcreate /dev/md0
$pvcreate /dev/md1
$pvcreate /dev/md2
$vgcreate vg_data1 /dev/md0
$vgcreate vg_data2 /dev/md1
$vgcreate vg_data3 /dev/md2
$lvcreate vg_data1 -n lv_data1 -L <size>
$lvcreate vg_data2 -n lv_data2 -L <size>
$lvcreate vg_data3 -n lv_data3 -L <size>
Then create your LUKS partition:
$cryptsetup -v --verify-passphrase luksFormat /dev/mapper/lv_data1 vg_data1-lv_data1_crypt
$cryptsetup -v --verify-passphrase luksFormat /dev/mapper/lv_data2 vg_data2-lv_data2_crypt
$cryptsetup -v --verify-passphrase luksFormat /dev/mapper/lv_data3 vg_data3-lv_data3_crypt
Then create your filesystem and mount them:
$mkfs.ext4 /dev/mapper/vg_data1-lv_data1_crypt
$mkfs.ext4 /dev/mapper/vg_data2-lv_data2_crypt
$mkfs.ext4 /dev/mapper/vg_data3-lv_data3_crypt
$mount -t ext4 /dev/mapper/vg_data1-lv_data1_crypt /mnt/data1
$mount -t ext4 /dev/mapper/vg_data2-lv_data2_crypt /mnt/data2
$mount -t ext4 /dev/mapper/vg_data3-lv_data3_crypt /mnt/data3
One of my systems looks like this. On this particular system I only encrypt home and swap:
$jschaeffer@zipmaster07 ~ $ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 111.8G 0 disk
\sda1 8:1 0 100M 0 part /boot/efi
\sda2 8:2 0 250M 0 part
\md0 9:0 0 250M 0 raid1 /boot
\sda3 8:3 0 111.5G 0 part
\md1 9:1 0 111.4G 0 raid1
\vg_sys1-lv_var1 (dm-1) 252:1 0 55G 0 lvm /var
\vg_sys1-lv_tmp1 (dm-2) 252:2 0 4G 0 lvm /tmp
\vg_sys1-lv_swap1 (dm-3) 252:3 0 6G 0 lvm
\vg_sys1-lv_swap1_crypt (dm-5) 252:5 0 6G 0 crypt [SWAP]
\vg_sys1-lv_root1 (dm-4) 252:4 0 46.4G 0 lvm /
sdb 8:16 0 111.8G 0 disk
\sdb1 8:17 0 100M 0 part
\sdb2 8:18 0 250M 0 part
\md0 9:0 0 250M 0 raid1 /boot
\sdb3 8:19 0 111.5G 0 part
\md1 9:1 0 111.4G 0 raid1
\vg_sys1-lv_var1 (dm-1) 252:1 0 55G 0 lvm /var
\vg_sys1-lv_tmp1 (dm-2) 252:2 0 4G 0 lvm /tmp
\vg_sys1-lv_swap1 (dm-3) 252:3 0 6G 0 lvm
\vg_sys1-lv_swap1_crypt (dm-5) 252:5 0 6G 0 crypt [SWAP]
\vg_sys1-lv_root1 (dm-4) 252:4 0 46.4G 0 lvm /
sdc 8:32 0 931.5G 0 disk
\sdc1 8:33 0 100M 0 part
\sdc2 8:34 0 931.4G 0 part
\vg_home1-lv_home1 (dm-0) 252:0 0 850G 0 lvm
\vg_home1-lv_home1_crypt (dm-6) 252:6 0 850G 0 crypt /home
sr0 11:0 1 3.8G 0 rom
Thanks,
Joshua Schaeffer