Arch Linux

kirth

Member

Registered: 2023-05-03

Posts: 5

Increase encrypted root partition size

Hi,
I'm quite new to Arch. Sorry for asking something already covered.
I installed the system using the provided script and did not pay enough attention to the partitions size (furthermore I made an error encrypting / instead of /home).

Anyway, I would like to increase the default 20 Gb on the root partition to at least 100 Gb.

Here there are some information about my disk and partitions:

$ sudo lsblk -o name,maj:min,rm,size,ro,type,fstype,label,mountpoint

NAME         MAJ:MIN RM  SIZE RO TYPE  FSTYPE      LABEL MOUNTPOINT
zram0        253:0    0    4G  0 disk                    [SWAP]
nvme0n1      259:0    0  1.8T  0 disk                    
├─nvme0n1p1  259:1    0  200M  0 part  vfat              /boot
├─nvme0n1p2  259:2    0 19.8G  0 part  crypto_LUKS       
│ └─cryptlvm 254:0    0 19.8G  0 crypt ext4              /
└─nvme0n1p3  259:3    0  1.8T  0 part  ext4              /home

$ sudo fdisk -l /dev/nvme0n1
Disk /dev/nvme0n1: 1.82 TiB, 2000398934016 bytes, 3907029168 sectors
Disk model: Samsung SSD 980 PRO 2TB                 
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x1a07cf75

Device         Boot    Start        End    Sectors  Size Id Type
/dev/nvme0n1p1 *        6144     415743     409600  200M  c W95 FAT32 (LBA)
/dev/nvme0n1p2        421888   41943039   41521152 19.8G 83 Linux
/dev/nvme0n1p3      41943040 3907028991 3865085952  1.8T 83 Linux

$ sudo parted /dev/nvme0n1 unit s print

Model: Samsung SSD 980 PRO 2TB (nvme)
Disk /dev/nvme0n1: 3907029168s
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags: 

Number  Start      End          Size         Type     File system  Flags
 1      6144s      415743s      409600s      primary  fat32        boot, lba
 2      421888s    41943039s    41521152s    primary
 3      41943040s  3907028991s  3865085952s  primary  ext4

I booted with a LiveCD and thought I could use  GParted to perform the following:

• cryptsetup luksOpen /dev/nvme0n1p2 cryptdisk

• Reduce /home (/dev/nvme0n1p3) shrinking from the left approx. 80 Gb

• Increase / (/dev/nvme0n1p2) to the right gaining those extra 80 Gb

Is this the correct way to proceed?

I'm scared to end up with a not bootable system.

Thanks a lot for your help.

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,255

Re: Increase encrypted root partition size

Should be fine from the methodology used but low level partitioning operations can always be hairy, make sure you have backups of stuff you need.