[dm-crypt] Need some suggestions on large drives

[Scott Castaline <skotchman@gmail.com>]

First, does anyone know how Fedora 12's installer installs LUKS with 
LVM2? Do they do LUKS over LVM2 or LVM2 over LUKS?

Second, I have my boot disk (WD 500GB) setup with 2 partitions, the 1st 
is non LVM or LUKS as ext4 300MB and used as the /boot. The rest of the 
drive or 2nd partition is my 1st VG which is all encrypted and is 
divided up with 7 LVs (/, /home, /dnlds, /docs, /graphics, /tmp, /var, 
swap01) I setup the swap01 with encrytion and is 1/2 of my total swap 
needed (4 GB of RAM total swap = 5 GB, 2.5GB swap01 + 2.5 GB swap02). Is 
this what you call mult-layed encryption? I saw that briefly mentioned 
in either the Aug 2009 or Sept 2009 archives. Am I wrong for doing that?

Third, I've been reading the discussion on the different encryption 
ciphers from the Aug 2009 archive and am thinking of using 
serpent-cbc-essiv:sha256. Would this be suitable for a 1TB drive? I'll 
be doing this manually so would I 1st create the partition with fdisk 
then the luksFormat finally doing the vgcreate and lvcreate. I'll be 
doing 2 seperate 1TB drives at the same time set up as separate VGs. One 
of them will also have an LV for swap02 which I was planning to 
additionally encrypt. Would this be wrong?

Finally, as mentioned in the second paragraph, I have /var as seperate 
LV which is within an encrypted VG. The LV is not additionally 
encrypted, I had to expand the LV using free space from the 1st VG. I 
did it through the GUI for LVM2. It never indicated any errors during 
the process and it appears now to have access to the full size of the 
expanded LV. However, I now get an error on boot referring to the LV 
that /var resides on. Does anyone know the proper way to use e2fsk? I 
tried shutting down to single user and unmounting the LV so that I could 
execute "e2fsck -VCa mapped-device", but I wasn't able to unmount the LV.

Sory for the long winded post and for going all over the place, but they 
are sort of inter-related and I'm trying to straighten them out all 
together.