Safely move (rarely changing) operating system directories to SSD drive

Question

I would like to move some directories that contain binaries to an SSD drive. How should I safely go about it?

1. /usr
2. /opt

Please consider safely emphasized.

[14.04.1]

Answer 1

1. Make a full system backup. (Read What's a good back-up strategy for 1 desktop PC? first)
2. Make a full file back-up (Déjà-dup, BackInTime, rsync, ...)
3. Boot the LiveCD of the Ubuntu version you're currently running
4. Go to gparted, choose the SSD, create a partition 25% larger then the total size of /usr and /opt, format as ext4
5. Get the blkid of the new partition
6. Make an additional back-up only of the fstab file
7. Edit the fstab of the system and add the correct mount parameters for the new partitions, but do not save yet!
8. cp --force --preserve --recursive --verbose /dev/HDD/opt /dev/SSD/opt 2>>/tmp/copy_error.txt (and usr too of course\
9. Verify there are no errors copying. If there are errors, correct manually.
10. Rename the old /opt and /usr to /opt_old and /usr_old
11. verify the copy with diff -r /dev/SSD/opt /dev/HDD/opt_old (and usr)
12. Save fstab
13. mount --all

If

(And that's a big if!)

1. for any of the steps above you go "Huh? What's that?"
2. you have an encrypted FS
3. you have any other kind of non-standard non-plain non-Vanilla Ubuntu install

don't do it!

Voilà: That's the safest way!