Arch Linux

That's actually a way better way of doing it :) I'm going to disown this package in favor of that idea.

Another easy way of achieving this is to make an extra copy of the encrypt hook. Call it encrypt2. Replace inside this script cryptkey with cryptkey2 and cryptdevice with cryptdevice2. Rebuild the initramfs. Then add cryptdevice2= to your boot options. and cryptkey2= if needed

I now it is not the cleanest way and definetly not that handy if you would need to unlock a lot of encrypted volumes, but for me this works.

Should maybe also cleanup the script a little more because it loads some stuff twice.

hope this is helpfull for someone

This hook is entirely broken with mkinitcpio 0.12.0. Please also consider depending on cryptsetup and renaming the hook rather than replacing it.

1.5.1 was released 2 months ago as well -- another reason not to provide cryptsetup.

When I boot with this:

kernel: Command line: BOOT_IMAGE=/vmlinuz-linux root=/dev/mapper/root ro cryptdevice=/dev/mapper/vg-root:root:allow-discards,/dev/mapper/vg-usr:usr:allow-discards

fstrim does not work. (While it does work on other devices activated in crypttab or manually and which are set up the same way as / and /usr, namely LUKS on LVM on the same volgroup/SSD.)

Adding an echo to the code of cryptsetup-multi, it turns out $cryptoptions is empty. I never see the messages "Enabling TRIM/discard support." or "Encryption option '${cryptopt}' not known, ignoring.".

Btw., I read about the kernel parameter root_trim=yes somewhere; it does not change anything in my case.

This worked for me, too. I had to change some paths in encrypt_install so that they began with /usr/lib/ to avoid warnings from mkinitcpio, though, as mentioned here:
https://bbs.archlinux.org/viewtopic.php?id=140390

Works ok only had to make a small change to the encrypt hook to make the cryptkey parameter work,
so it unlocks all disks without prompting for a password(if they use the same keyfile)

You need to call "rm -f ${ckeyfile}" outside of the loop.
The end of /lib/initcpio/hooks/encrypt should look like this

fi
# rm -f ${ckeyfile}
done
fi
rm -f ${ckeyfile}
}

Specify multiple devices (seperated by commas) in the cryptsetup parameter, e.g.
kernel /vmlinuz26 cryptdevice=/dev/sda4:volgroup,/dev/sdb1:volextend root=/dev/mapper/volgroup-root ro

This is a package of the work of delcypher:
https://bbs.archlinux.org/viewtopic.php?id=105086