BTRFS for new users. Why you should consider it.

[GreyGeek]

Ah, personal taste!
I always ro both my @ and @home snapshots, and send them to remote storage. If I need to rollback I take a snapshots of the backups with out using “-r”.


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[GreyGeek]

BTRFS for new users. Why you should consider it.

*deletes brain fart*

[vinnywright]

OK, I tried the three steps and they worked, so I guess I did get it right. However, when I list the subvolume, I not only get @ and @home, but also two others: './' and '../'. What are those?

those are ,,,,,,,well like links to the current directory ./ and the next directory up ../

you will find them in every directory ,,,,,,,,,,,,exampel

vinny@vinny-Bonobo-Extreme:/mnt/test$ ll
total 20
drwxr-xr-x 1 root root  242 Dec  4 20:32 ./
drwxr-xr-x 4 root root 4096 Aug 22 22:08 ../
drwxr-xr-x 1 root root  244 Feb  2 20:46 @/
drwxr-xr-x 1 root root  244 Feb  1 21:34 @17.04/
drwxr-xr-x 1 root root  244 Dec  2 14:55 @17.04_171204-202339/
drwxr-xr-x 1 root root  244 Nov  7 21:24 @_171204-203229/
drwxr-xr-x 1 root root   10 Apr 12  2016 @home/
drwxr-xr-x 1 root root   30 Apr 17  2017 @home17.04/
drwxr-xr-x 1 root root   30 Apr 17  2017 @home17.04_171204-203017/
drwxr-xr-x 1 root root   10 Apr 12  2016 @home_171204-203128/
drwxr-xr-x 1 root root  114 Apr 21  2017 ubiquity-apt-clone/
drwxr-xr-x 1 root root    6 Apr 22  2017 var/

vinny@vinny-Bonobo-Extreme:[COLOR=#FF9999]/mnt/test[/COLOR]$ cd ..                                                                                                                   
vinny@vinny-Bonobo-Extreme:[COLOR=#FF9999]/mnt[/COLOR]$

vinny@vinny-Bonobo-Extreme:/mnt$ ll
total 24
[COLOR=#FF9999]drwxr-xr-x  4 root root 4096 Aug 22 22:08 ./
drwxr-xr-x 24 root root 4096 Feb 15 14:51 ../[/COLOR]
drwxr-xr-x  1 root root   86 Sep 26 20:04 btrfs/
drwxr-xr-x  1 root root  242 Dec  4 20:32 test/

see hear they are again

VINNY

[jlittle]

OK, I tried the three steps and they worked, so I guess I did get it right. However, when I list the subvolume, I not only get @ and @home, but also two others: './' and '../'. What are those?

Well, you asked, a boring explanation in excruciating detail follows.

I imagine you are typing ll /subvol as oshunluvr suggested. That command is typically an alias, and I think your alias includes the -a switch, which causes the entries for . and .. to be included. These are present in every directory, and are links back to the directory itself and its parent respectively. (This is an ancient Unix practice; the command line has 5 decades of accumulated quirks like this.) If I run type ll:

$ type ll
ll is aliased to `ls --color -lh'

Note no -a. I think yours will have -a, or maybe combined with other switches, something like -la. The -a just shows files that begin with a dot, and some people like to always see them. I think you've got a -F as well; that adds a slash, "/", to directories.

I think it's better not to suggest someone run something that is typically an alias, like ll; if their alias is defined differently confusion can be the result. Heck, I confuse myself with aliases I've long forgotten that I've set up.

[oshunluvr]

Those mean "this directory" and "up one directory". Those are always there, just not visible unless you use the "-a" switch when listing the directory. The "ll" command I had you do is an alias command for "ls -la". The "-l" means "long listing" and the "-a" means "list all files including hidden"

If you go back to Dolphin now, the /subvol folder is under "Root" and will show the two subvolumes.

[oldgeek]

Thanks for the answers from all three of you. I just wanted to know if I was doing everything right. I've never bothered with btrfs before, but since I'm retired and have time on my hands I thought I'd give it a try before I decide what to do when the official 18.04 release comes out. Now to check out oshunluvr's previous posts to learn more.

[oldgeek]

Oops. I reloaded Bionic on my VMM, went to Dolphin, found subvol, but it's empty. Used the ll /subvol command on Konsole and it does not show @ or @home. Where did they go?

[vinnywright]

Oops. I reloaded Bionic on my VMM, went to Dolphin, found subvol, but it's empty. Used the ll /subvol command on Konsole and it does not show @ or @home. Where did they go?

if you rebooted you will half to remount it ,,,,step 2 in post #29

VINNY

[GreyGeek]

By “reload” do you mean re-install?


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[oshunluvr]

Oldgeek: Here, and I suggest this to you, I add my root file system to fstab so it's mounted and visible at boot up. This makes snapshots and etc. easier because you don't have to re-mount each time you want to do a snapshot or whatever you're doing. And it's pretty easy to do:

Hit ALT-F2 on your keyboard. This opens the Krunner bar at the top of your screen. Type this in it: kate /etc/fstab and ENTER. This will launch Kate text editor with your fstab loaded. Find the line in your fstab that looks like this:

UUID=8f0c1661-4e84-4512-b875-23bcfd5be1d8 /               btrfs   defaults,subvol=@ 0 1

Your UUID will be different than the above and there may be other differences. No matter because your only going to change three things.
Now highlight and copy that line, paste it below the above line, and edit it so it looks like this. I underlined the edits and lined through what to delete:

UUID=8f0c1661-4e84-4512-b875-23bcfd5be1d8 /[U]subvol[/U]      btrfs defaults[S],subvol=@Ubuntu_16_04[/S] 0 [U]0[/U]

The end result will look like this:

UUID=8f0c1661-4e84-4512-b875-23bcfd5be1d8 /subvol      btrfs defaults 0 0

Then save the file - it will ask for your password because it's owned by root.

Now the next reboot /subvol will be mounted. You can mount it now by opening a terminal and typing sudo mount -a

[oldgeek]

Did that and it works. Thanks.

[ukdave]

Been thinking of using BTRFS file system for awhile now but have always been a bit nervous of doing so. Having read all the excellent information in this thread I am now going to use it. I have a golden opportunity now as I have finally kicked windows off my system and got a new SSD.
Many thanks to those who have taken the time to explain how BTRFS works.

[oshunluvr]

Shameless plug here: https://store.kde.org/p/1214134/

I wrote this a while back and several users here have reported it's usefulness.

It allows you the manage your subvolumes (snapshots, backups, etc.) without going to the command line. Try it and let me know what you think.

[GreyGeek]

It is a move you will not regret.

Want to experiment with something that may change your system significantly but don’t want to spend hours or days undoing what you did? Just snapshot @ and @home and carry on. If things don’t work out it will take less than 5 minutes to rollback and reboot.

Inadvertently delete a file or folder? Mount @snapshot or @homesnapshot and browse it to the files or folder you want to restore then drag & drop it into /or /Home/yourname.

Create a subvolume called @data in <ROOT_OS> and mount it in /etc/fstab as /Home/yourname/data

Then create snapshots of @data independently of /home and send & receive them to external storage for backup.

Learn your Btrfs commands and use them in a root Konsol to do your maintenance. TimeShift is the best of the maintenance GUI’s but they all have weakness that doing things manually doesn’t have. (If you do use TimeShift but later decide to remove it BE SURE you delete all the snapshots you made with it BEFORE you delete it, otherwise you will hose your system

[ukdave]

Thanks oshunluvr and GreyGeek.
I do have a question before I take the plunge.
What would be the best thing for my drive set up, I have 2x 250GB SSD, 1x 250GB M2 and 1x 2TB HDD?
I would like to use the 2TB HDD for data backup and I do plan to boot different linux os.
Do I need to worry about uefi or can I just switch it off in my bios?
Many thanks for your help