BTRFS Layout

English Install/Boot/Login
1

Hi all,

I am wondering what the @ in the output of:

btrfs subvolume list /

ID 256 gen 30 top level 5 path @
ID 257 gen 436 top level 256 path @/var
ID 258 gen 150 top level 256 path @/usr/local
ID 259 gen 436 top level 256 path @/tmp
ID 260 gen 369 top level 256 path @/srv
ID 261 gen 436 top level 256 path @/root
ID 262 gen 34 top level 256 path @/opt
ID 263 gen 124 top level 256 path @/boot/grub2/x86_64-efi
ID 264 gen 26 top level 256 path @/boot/grub2/i386-pc
ID 265 gen 419 top level 256 path @/.snapshots
ID 266 gen 436 top level 265 path @/.snapshots/1/snapshot
ID 274 gen 58 top level 265 path @/.snapshots/2/snapshot
ID 275 gen 65 top level 265 path @/.snapshots/3/snapshot
ID 276 gen 66 top level 265 path @/.snapshots/4/snapshot
ID 277 gen 67 top level 265 path @/.snapshots/5/snapshot
ID 280 gen 136 top level 265 path @/.snapshots/6/snapshot
ID 281 gen 138 top level 265 path @/.snapshots/7/snapshot
ID 282 gen 145 top level 265 path @/.snapshots/8/snapshot
ID 283 gen 146 top level 265 path @/.snapshots/9/snapshot
ID 284 gen 147 top level 265 path @/.snapshots/10/snapshot
ID 285 gen 149 top level 265 path @/.snapshots/11/snapshot
ID 286 gen 363 top level 265 path @/.snapshots/12/snapshot
ID 287 gen 364 top level 265 path @/.snapshots/13/snapshot
ID 288 gen 365 top level 265 path @/.snapshots/14/snapshot
ID 289 gen 366 top level 265 path @/.snapshots/15/snapshot
ID 290 gen 369 top level 257 path @/var/lib/machines
ID 291 gen 371 top level 265 path @/.snapshots/16/snapshot
ID 292 gen 373 top level 265 path @/.snapshots/17/snapshot
ID 293 gen 416 top level 265 path @/.snapshots/18/snapshot
ID 294 gen 418 top level 265 path @/.snapshots/19/snapshot

means? Does it symbolize the root fs?
Is it created via the

btrfs subvolume create

command?

Thanks for explaining that that!

I am trying to apply the btrfs layout of Opensuse to Slackware-Current, cause it trust Opensuse has the most experience with it :slight_smile:

rehcla

2

I have no experience with Btrfs whatsoever, but I consulted the man page

man btrfs-subvolume

and there it says (extract):

For every subvolume the following information is shown by default:

ID <ID> gen <generation> top level <ID> path <path>

… path is the relative path of the subvolume to the top level subvolume.

Thus IMHO the @ stands for the top level subvolume (which in your case is the / from your command).

3

It does not.

Legacy. I think it could be inherited from zfs that is using @ as reference to snapshot.

At some point @ was introduced as root subvolume (to move things from top level subolume/filesystem root); today SUSE settled on using subvolumes under .snapshots and @ remained simply because nothing is gained by removing it.

Is it created via the

btrfs subvolume create 

 command?

yes.