Hello, On Oct 17 14:32 Carlos E. R. wrote (excerpt):
It would be nice if there were a script or something to create all those volumes, used during installation, so that the admin could recreate them easily.
There is something like that but only to create a single subvolume and currently its usefulness is limited on SLE12 and Leap 42.1 (perhaps it gets better on Tumbleweed): /usr/sbin/mksubvolume (it belongs to the snapper RPM) See "man mksubvolume". What is currently missing is that mksubvolume creates parent directories as needed: --------------------------------------------------------- # mksubvolume /var/mystuff/mysubvol failure (parent of target does not exist) --------------------------------------------------------- In this case a manual "mkdir /var/mystuff/" is needed: --------------------------------------------------------- # mkdir /var/mystuff # mksubvolume /var/mystuff/mysubvol --------------------------------------------------------- What is currently also missing is that mksubvolume can correctly remove such a subvolume because only something like "btrfs subvolume delete /var/mystuff/mysubvol" is insufficient and it does not work this way: --------------------------------------------------------------- # btrfs subvolume delete /var/mystuff/mysubvol Delete subvolume (no-commit): '/var/mystuff/mysubvol' ERROR: cannot delete '/var/mystuff/mysubvol': Invalid argument --------------------------------------------------------------- It is more complicated to delete such a subvolume, cf: ------------------------------------------------------------------- # btrfs subvolume list -a / | grep mystuff ID 306 gen 5933 top level 257 path <FS_TREE>/@/var/mystuff/mysubvol ------------------------------------------------------------------- I leave it to the reader to find out how to delete such a subvolume (hint: inspect my script below ;-) But if only the subvolume is deleted it leads to "interesting effects" during the next reboot: You will find yourself in systemd's emergency mode because the /var/mystuff/mysubvol entry in /etc/fstab is still there but that one cannot be mounted (because the subvolume is deleted). Solution is to manually remove the /var/mystuff/mysubvol entry from /etc/fstab. Caution: What results totally wrongly created subvolumes for the SLE12 default btrfs subvolume structure is: -------------------------------------------------------------------------------- # btrfs subvolume create /var/mystuff/mysubvol2 Create subvolume '/var/mystuff/mysubvol2' # btrfs subvolume list -a / | grep mystuff ID 307 gen 5945 top level 259 path @/.snapshots/1/snapshot/var/mystuff/mysubvol2 -------------------------------------------------------------------------------- It is created under @/.snapshots/1/snapshot/ which is plain wrong. Better delete that subvolume right now: ---------------------------------------------------------- # btrfs subvolume delete /var/mystuff/mysubvol2 Delete subvolume (no-commit): '/var/mystuff/mysubvol2' ---------------------------------------------------------- FYI: Mainly for documentation here my selfmade script that I used on SLE12 before I learned that /usr/sbin/mksubvolume exits. This script shows how complicate it is to cerate a subvolume in compliance with the SLE12 default btrfs subvolume structure (long lines may get shown wrapped via e-mail): ------------------------------------------------------------------------- #!/bin/bash set -u -e -o pipefail # the code below fails if there is a leading slash: mysubvol=${1#/} # find out what subvolume on what device node is mounted at '/': output=( $(findmnt -nrv -t btrfs -o TARGET,SOURCE,FSROOT | grep '^/ ' ) ) # TARGET is '/' (by grep) # SOURCE is the device node that is mounted at the target '/': device=${output[1]} # FSROOT is the subvolume that is mounted at the target '/': fsroot=${output[2]} # if a '/@/.snapshots/...' subvolume is mounted at the target '/' # we assume the SLE12 btrfs default structure is used: if [[ $fsroot == "/@/.snapshots/"* ]] ; then # mount btrfs at its root subvolume: btrfsroot=$( mktemp -d /tmp/btrfsroot.XXXXXXXXXX ) mount -t btrfs -o subvolid=0 $device $btrfsroot # create subvolume under /@/: mkdir -p $btrfsroot/@/$( dirname $mysubvol ) btrfs subvolume create $btrfsroot/@/$mysubvol # btrfs at its root subvolume is no longer needed: umount $btrfsroot rmdir $btrfsroot # mount subvolume: output=( $( btrfs subvolume list -a / | grep "/@/$mysubvol" ) ) id=${output[1]} mkdir -p /$mysubvol mount -t btrfs -o subvolid=$id $device /$mysubvol # make entry in /etc/fstab: if ! grep -q "subvol=@/$mysubvol" /etc/fstab ; then uuid=$( for l in /dev/disk/by-uuid/* ; do readlink -e $l | grep -q $device && basename $l ; done ) echo "UUID=$uuid /$mysubvol btrfs subvol=@/$mysubvol 0 0" >>/etc/fstab fi else echo "Unexpected exit: No '/@/.snapshots/...' subvolume mounted at '/'." exit 99 fi ------------------------------------------------------------------------- This script is only my personal hack that I used for SLE12. It seemed to work for me on SLE12 but I have not at all tested it thoroughly and I never used it on Leap or Tumbleweed. Kind Regards Johannes Meixner -- SUSE LINUX GmbH - GF: Felix Imendoerffer, Jane Smithard, Graham Norton - HRB 21284 (AG Nuernberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org