[SOLVED] UEFI installation with Btrfs.

[phonic-otg]

Following Qqmike's "How To" for UEFI install I installed 18.04 onto a 240Gb M.2 SSD, with ESP (240Mb), Btrfs (190Gb) and swap (33Gb) all great.

Moved on to Grey Geeks BTRFS "How To" and have a slight issue with the BTRFS formated USB with 59G space by (KPM) .
After Formatting I unmounted and removed the USB and reinserted it but the system still wont write to the USB even though it is seen. The one error pop up was about editing /etc/fstab, was not sure, so left that for now.
I have reformatted the USB and then tried rebooting twice.

PS: BLISTERINGLY FAST boot with UEFI on SSD. wow!!!!!!

***---FOR QUICKNESS GO TO POST#4---***
So far all is better than the earlier install (still on a disconnected HD)

Some advice to the btrfs USB being mounted properly.
I did try manually without success

*** Better Description ***

I kept noticing each time I tried to reformat the USB, where KPM would do its scan and then flash the original neon partition info quickly and ultimately show the btrfs partition that was formatted.
Then Device Notifier in system tray would pop up with the neon info for the drive after I delete the btrfs to start again.
Suspecting some criss cross mishmash I decided to shred the partition in hopes when reformatting it to BTRFS all will be zen.

I realised after shredding the USB and the Neon install was still there and remembered I installed the ISO to USB with RosaImageWriter and had to clear it with rosa from my laptop whence it originated. Did that, no more Neon on USB. Reformatted it BTRFS.

[phonic-otg]

Some advice to the btrfs USB being mounted properly.
I did try manually without success

Wierd

[GreyGeek]

Check the man page for mount. You've got the syntax totally wrong.
It looks like you've already tried to mount something on /media. Were you successful using good syntax?

Let's assume that you've mounted your Btrfs <ROOT_FS> on /mnt
sudo -i
mount /dev/disk/by-uuid/yoursda1uuid /mnt
It contains:
@
@home
snapshots

In /mnt/snapshots you have saved
@_YYYYMMDD
@home_YYYMMDD

Those represent your normal snapshot pair, made at the same time (within a minute or so). You will use them to restore @ and @home if something goes wrong. You might end up with two or three more pair, deleting the oldest before you create the newest.

You love to take photos and movies. These files are generally already compressed so further compression is not needed. You buy a 4TB HD (spinning disk, not SSD) and install it in your second HD bay. The system tags it as sdb. Then you use KPM to create the only partition, sdb1, and format it using btrfs and without designating a mount point like "@" or "@home" or "/" or "/home" The blkid command gives you its uuid. You create a subdirectory under /home/youracct called /home/youracct/photos_movies. You are going to mount /dev/sdb1 to that subdirectory.

As root you edit /etc/fstab and add
UUID=whatevertheuuidis btrfs defaults /home/youracct/photos_movies 0 3
^^^^^^^^^
could be /dev/sdb1 but if you ever plug in another HD that value could switch on you to something else. UUID's don't switch.

When you reboot you should see the subdirectory under your account titled photos_movies. It should have you:you as owner:group.

Since it is actually a btrfs subvolume it's contents will not be captured when you snapshot @home because nested subvolumes are never included. When you snapshot @ and browse through the snapshot you'll notice that @home under @ is empty. That's why it is snapshotted independently. If you mounted /dev/sdb1 to, say, /media then all you'd see is a listing of photos and movies. If you created two subdirectories, photos and movies under /home/youracct/photos_movies, they'd show up in a listing as

vdir /media
photos
movies
Since photos and movies are subdirectories and not subvolumes you cannot snapshot them. If, however, you used to the
sudo btrfs su cr /media/photos
sudo btrfs su cr /media/movies
then they are subvolumes which can be snapshotted and you could create a hidden subdirectory called .snapshots to store them in: mkdir /home/youracct/photos_movies/.snapshots
IF the hidden option is checked in Dolphin that subdirectory won't show in normal listings, but that won't stop you from snapshotting photos and movies into that subdirectory.

[phonic-otg]

Isuue Sorted

Check the man page for mount. You've got the syntax totally wrong.
It looks like you've already tried to mount something on /media. Were you successful using good syntax?

ALL IS GOOD!

After creating, one needs to mount their btrfs formatted usb before sending "in root" with

mount /dev/disk/by-uuid/[HL][B][I]your_btrfs_formatted_usb-uuid[/I][/B][/HL] /mnt

Then send @ "in root" with

btrfs send /mnt/snapshots/@_basic_install | btrfs receive /media/[I]user-name[/I]/[I]the_btrfs_usb[/I]

Follow for @home "in root" with

btrfs send /mnt/snapshots/@home_basic_install | btrfs receive /media/[I]user-name[/I]/[I]the_btrfs_usb[/I]

to get

root@phonic-photonic:~# btrfs send /mnt/snapshots/@_basic_install | btrfs receive /media/phonic/Snapshots_18.04/
At subvol /mnt/snapshots/@_basic_install
At subvol @_basic_install
root@phonic-photonic:~# btrfs send /mnt/snapshots/@home_basic_install | btrfs receive /media/phonic/Snapshots_18.04/
At subvol /mnt/snapshots/@home_basic_install
At subvol @home_basic_install
root@phonic-photonic:~#

***this is how it works for me. ***

Then one needs to unmount their btrfs formatted usb cleanly (before being able to eject the drive from Device Notifier from the System Tray!) "as root" with

umount /dev/disk/by-uuid/[HL][B][I]your_btrfs_formatted_usb-uuid[/I][/B][/HL] /mnt

THANKS Y'ALL ARE THE BEST.

[GreyGeek]

I think you got it! Way to go!

Never again do you have to waste hours or days trying to reverse a problem.

[phonic-otg]

Never again do you have to waste hours or days trying to reverse a problem.

Thank you for your guide it helped immensely.
About to do another backup now that Mail, Browser-settings (synced), VPN and general look and feel are all set.