Resizing encrypted partitions

[apamix]

Hello everybody,

I have one little big problem. I Have a encrypted hdd but the root partition is to little :(



[root@PCrevisie:/# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/PCrevisie-root
322M 292M 14M 96% /
tmpfs 1013M 0 1013M 0% /lib/init/rw
udev 1008M 228K 1008M 1% /dev
tmpfs 1013M 4.0K 1013M 1% /dev/shm
/dev/sda1 228M 16M 201M 7% /boot
/dev/mapper/PCrevisie-home
58G 36G 20G 65% /home
So my idea is now to cut 1GB from the /home partition and add it to the root partition but I will need some help. After I read some tutorials I think the prodcedure must go this way :

1) BACK UP before I start crying

2) Boot the live cd and then :



sudo apt-get update && sudo apt-get install lvm2 cryptsetup

# Loading it to kernel
sudo modprobe dm-crypt

# Open the encrypted partition

sudo cryptsetup luksOpen /dev/sda2 crypt1

# And we must recognize him.
sudo vgscan --mknodes
sudo vgchange -ay

Here was easy and I think I will have no problems.. but now come the hard part. And I'm not sure about it so here I will need some help. I think will be something like :



# Checking the partition for errors
sudo e2fsck -f /dev/mapper/PCrevisie-home
# Because I want to reduce the home partition with 1GB
sudo lvreduce -L -1G /dev/PCrevisie/home
# Now I want to add this 1GB to the root partition
lvresize -L +1G /dev/PCrevisie/root
#Now I Need to lock the partition again
sudo pvchange -x n /dev/mapper/crypt1
#And now I must resize the filesystem
sudo e2fsck -f /dev/mapper/PCrevisie-root
sudo resize2fs -p /dev/mapper/PCrevisie-root
If I'm getting somewhere wrong will be very nice to get some assist.

[WthIteh]

Before reducing size of logical volume using lvreduce, it's required to reduce size of the filesystem. Otherwise lvreduce may corrupt it.
For reducing size of filesystem of /dev/mapper/PCrevisie-home you may use gparted.
Other parts of your process are OK.

[apamix]

Ok ;)) Here I got wrong :P

Why I must reduce the filesystem when I just migrate the free place from /home to the root partition :)

Thanks in advance for the answer :popcorn:

[WthIteh]

The logical volume in respect to the filesystem is like physical hard disk in non-LVM configurations. The filesystem of /home have thought it has n GB and so it may have placed some data at the end of its n GB space (some file creation/removal may lead to empty holes within the partition space). So reducing 1 GB by lvreduce without reducing filesystem itself first, can corrupt all files which are placed at the end of partition by filesystem (which is possible even if the partition has enough free space).

Indeed you do not move free space. You first remove it from one logical volume and when this task was finished completely, you add it to another independent logical volume ;)

[apamix]

Thanks for the good info :popcorn:.