LVM on LUKS split across drives

Question

I'm installing LVM on LUKS, as follows:
/dev/sda1: boot
/dev/sda2: first LUKS device
/dev/sdb1: second LUKS device
/dev/sda2 and /dev/sdb1 are in a volume group, which is then split into logical volumes.
/dev/sda2 and /dev/sdb1 have the same password.
How can I only be prompted once for this password at boot?

Answer 1

Strike0 has told me in the past that this is actually supported.  Just use the LVM2 hook twice, once before and once after the encrypt hook.  There is also the cryptsetup-multi package, but it is partially broken. In these forums somewhere there are instructions from falconindy on using the hook (maybe the install) file from the multi package in the current cryptsetup package.  but you are going to have to seach for that yourself.