Arch Linux

robin67

Member

From: the Netherlands

Registered: 2012-02-18

Posts: 45

2 question concerning LVM over LUKS

I succesfully configured LVM over LUKS, but have 2 parts that are not 100% clear to me

My setup is now
/dev/vda1       /boot
/dev/vda2       LVM2 with volumegroup name lvm holding three logical volumes: lvm-root, lvm-home, lvm-swap

The following I am wondering if someone would like to clarify to me

1. For booting I added cryptdevice to my kernel with the following parameter settings

       kernel /vmlinuz-linux cryptdevice=/dev/vda2:encrypted root=/dev/mapper/lvm-root ro

    It doesn't seems to matter what name I use in the red part of cryptdevice.
    So why do I need to put a name in this red part ?? Does it matter at all what name I use here ??

2. I did not fill in anyhting in /etc/crypttab and all seems to be working without issues.
    I could have entered something like "encrypted             /dev/vda2           none           luks" in it....

    What good would it do me to enter anything in crypttab ?? When would I really need this to be filled in ??

Hoping someone would mind to explains this to me .... thx

alphaniner

Member

From: Ancapistan

Registered: 2010-07-12

Posts: 2,810

Re: 2 question concerning LVM over LUKS

I just started playing with encryption so take what I say with a block of salt.

The name you give is what will show up in /dev/mapper, ie /dev/mapper/encrypted in this case.  Since you're using lvm I think you could change the name every boot if you wanted.  OTOH, if you formatted the partition directly, you could use the /dev/mapper/encrypted in fstab for example.

On the subject of crypttab I can't help you, except to say that in my experiments with encryption I've never touched it.

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