Arch Linux

eMxyzptlk

Member

Registered: 2008-02-04

Posts: 7

LVM over DM-CRYPT

Hello,

I used to be an ArchLinux user ( old username _Gandalf_ if anyone remembers me )  and I moved to Gentoo since a while, anyway I'd like to have an ArchLinux installation as well but I have a Question first:

Here's how my HDD is formatted:
/dev/sda1  --> /boot
/dev/sda2  --> DM-CRYPT --> LVM --> Swap, Root, Storage, Home, Gentoo and hopefully Arch.

does Arch support this kind of setup hopefully without rebuilding the kernel or hack the initrd image?? if not are there any guides??

Thanks...

gothmog.todi

Member

From: Austria

Registered: 2007-07-18

Posts: 120

Re: LVM over DM-CRYPT

Welcome back! (Sooner or later they all come back... )

From a short look at rc.sysinit i would say that your setup is supported. You will need to change a few settings to use it, though. Mainly you need to add encrypt and lvm2 to the HOOKS array in /etc/mkinitcpio.conf, adapt the boot parameter in your grub/lilo config and change USELVM in /etc/rc.conf to "yes"

There are some wiki entries about this:
http://wiki.archlinux.org/index.php/Sys … r_dm-crypt for dm-crypt
http://wiki.archlinux.org/index.php/Ins … AID_or_LVM for lvm
http://wiki.archlinux.org/index.php/RAID_Encryption_LVM for both combined
(the last one is rather old, some things may be out of date)

scorpyn

Member

From: Sweden

Registered: 2008-01-29

Posts: 66

Re: LVM over DM-CRYPT

Debian can do it so I know it's possible, but it's not covered by the wiki. I tried it myself, but after rebooting a few times and either only being able to decrypt but not set up the lvm stuff, or seeing the boot process not even try to unlock the lvm partition, I gave up and decided to only use 2 passworded partitions (/ and /home).

I'm guessing that I'm missing something very simple, but I don't know what...

toki

Member

From: Germany

Registered: 2007-12-27

Posts: 9

Re: LVM over DM-CRYPT

My setup is similar. I stole the whole idea from the debian installer and adapted it to arch
Here's how:

1.) modify /etc/mkinitcpio.conf

MODULES="ahci libata dm-mod dm-crypt aes-x86-64"
...
HOOKS="base udev sata usbinput keymap encrypt lvm2 filesystems"

Of course replace aes-x86-64 with your crypto system (eg. aes-generic).
Run mkinitcpio.

2.) in /etc/rc.conf:

USELVM="yes"

3.) in /boot/grub/menu.lst, you need:

kernel /vmlinuz26 cryptdevice=/dev/sda2:crypthd1 root=/dev/mapper/cryptodisks-root resume=/dev/mapper/cryptodisks-swap ...

Change the mapper stuff according to your system.

4.) don't forget about changing /etc/fstab.

I run it this way, and IIRC that's all it took to get it up and running, because the arch initscripts already provide support for this kind of setup.

poor_kenny

Member

Registered: 2008-05-14

Posts: 13

Re: LVM over DM-CRYPT

i;m trying to do the same setup as described in wiki... is a separate volume in LVM for /tmp necessary?

elide

Member

From: Russia

Registered: 2007-12-02

Posts: 40

Re: LVM over DM-CRYPT

Keeping your /tmp on tmpfs is a much better idea.