After several changes by the user, the final storage proposal looks like this: "2015-10-31 04:08:13 <1> (none)(3139) [libstorage] Storage.cc(dumpCommitInfos):4876 ChangeText Delete partition /dev/sdb2 (43.95 GiB) [destructive] Create volume /dev/sdb2 (43.94 GiB) Create volume /dev/sdb8 (7.84 MiB) Create volume group system (43.93 GiB) from /dev/sdb2 /dev/sdb8 [destructive] Create logical volume /dev/system/home (26.36 GiB) for /home with xfs Create root volume /dev/system/root (17.57 GiB) with btrfs Create subvolume ... Create subvolume ... ... Use /dev/sda2 as swap" I.e. it's not just a tiny 7.8 MiB partition that is proposed, it's an LVM logical volume with /dev/sdb2 (43.94 GiB) and that small /dev/sdb8 (7.84 MiB) for a total of 43.93 GiB.