NAS setup recommendations

[Matthias Play]

Hi,

since I am about to setup a NAS box for private and business usage (it 
will also be providing additional services), I would like to ask for 
recommendations on what I might use. Maybe somebody already had similar 
intentions and realized that setup.

The hardware is already in place and it basically contains HW proposed 
here (except for the HDD configuration and wih an additional 480G SSD 
for swapcache): 
http://blog.brianmoses.net/2015/01/diy-nas-2015-edition.html.

Ideally I would like to setup a RAID1 with a small boot partition and 
encrypting the rest just like it is demonstrated in encrypted_root.sh in 
the /usr/share/examples/rcconfig dir of a DragonFly installation.

My high level requirements are:
1. encrypt as much as possible i.e., also / if possible
2. implement resilience to minimize down times
3. using hammer as the predominant file system to allow for fine grained 
fs snapshots

In order to also support RAID1 I tried to set up vinum before encrypting 
the vinum volume with dm. But this has not worked out, maybe I did 
something wrong in configuring the loader variables for initrd. I read 
that it was planned to add mirror support in dm, but it has not been 
implemented so far. Maybe the reason is that with hammer there is 
already a descent mirror solution available. Although I think hammer 
mirror does not suit me 100% because of the expected down time in case 
of the master drive failing i.e., on would have to convert slave pfs to 
master pfs or cpdup the slave pfs contents to newly setup master pfs.

Is there a configuration I might use to realize my three requirements above?
Would using LVM be a viable alternative?

Regards
Matthas