Finally we decide and we already have the updated house servant!! The hardware that runs at present is:

• CPU: AMD Phenom (tm) 8450 Triple-Core Processor
• RAM: 4 x 1GiB Kingston DDR2 800MHz
• HD: 2 x 200GiB Digital Western
• Mobo: Gigabyte GA-MA78GM-S2H

We might have started the system that we had installed since the previous processor also belonged to the family x86_64 but we decide to realize a new installation since we wanted to mount servants virtualizados as what the system with the hypervisor, in this case KVM, does not need to have everything what had the ancient servant.

dm-crypt basically it is an encriptador of divisions that can serve to us to protect our information p.e. in ours / home.
After having used during a time cgd, I chose to throw a glance to EncFS but it was lacking functionalities that I believe necessary to support my safe information. Finally and after checking the available options, I have begun using dm-crypt.
To start we have to install sys-fs/cryptsetup:
it emerges-Dv cryptsetup
On the other hand, if we use our own kernel we will have to give him the support necessary for the encriptación algorithms and device-mapper. If on the other hand we use sys-kernel/genkernel probably we already will have the necessary support.
Now I will describe the steps to prepare the division encriptada:

• We create the division:
  # cryptsetup - and believe home/dev/sdX
• We verify if it has worked:
  # dmsetup ls it should list home
• The moment to give format:
  # mkreiserfs/dev/mapper/home
• Finally we prove it:
  # mount/dev/mapper/home/home
• We form the starter parameters:
• to add to/etc/conf.d/cryptfs the lines mount ='home’ and source = '/dev/sdX’

to add to / etc / fstab the line/dev/mapper/home/home
reiserfs noatime, nodev, nosuid 0 1

Remember the password asked for cryptsetup when we create the division since it will be asked us whenever we should start.