On Ubuntu 11.10, is it possible to decrypt 2 hard disks encrypted with LUKS / LVM by entering only one passphrase at boot?

I finally find a trick to enter only one password and have all my physical disks encrypted.

I encrypt the first one with a passphrase, I encrypt the second one using a keyfile that I store on the first hard drive (/root/mykeyfile).

And with the corrects line in /etc/crypttab file, it does the trick.

Update /etc/crypttab

sda5_crypt UUID=fb07f1e8-a569-4db9-9fd7-fc1994e093b5 none luks

sdb1_crypt UUID=4c0687f0-d7af-4f2e-9c57-5ca8e909d492 /root/mykeyfile luks