[CentOS] Best configuration for encrypted software RAID 1?

Wed May 15 16:42:39 UTC 2013
SilverTip257 <silvertip257 at gmail.com>

On Wed, May 15, 2013 at 12:25 PM, Digimer <lists at alteeve.ca> wrote:

> On 05/15/2013 12:22 PM, Dave Johansen wrote:
> > I'm setting up a computer with CentOS 6.4 and a mirrored software
> > RAID. I would like it to be encrypted so I was wondering what the best
> > configuration is. The only info I could find is
> > http://lists.centos.org/pipermail/centos-docs/2008-October/001912.html
> > but it appears to be a bit old and the info on the wiki (
> > http://wiki.centos.org/HowTos/EncryptTmpSwapHome ) doesn't seem to
> > address RAIDs.
> >
> > My main question is will it be better to encrypt the RAID itself or
> > the two partitions used by the RAID? Any other things I should be
> > aware of?
> >
> > Thanks,
> > Dave
> This depends on your use-case. Personally, I want my servers to be able
> to boot headless, so I leave /boot, <swap> and / unencrypted, RAID or

/boot absolutely can't be encrypted

I use LUKS in conjunction with Serial over LAN ... otherwise I'd have to
manually mount (or script it) so my encrypted volume is mounted.  In my
case as well, I only have the volume where my backup data goes ... so
/boot, /, and others are not encrypted (no need).

> not. Then I encrypt the LV (or partition) I am going to put data I care
> about on. I don't think there is any benefit to encrypting the
> partitions behind the MD device as it won't be able to form until you
> decrypt the devices. I'd keep crypt on the resulting /dev/mdX, at the
> lowest.

Create a software raid array and then create your LUKS encrypted volume on
top of that md device.  It is *highly recommended* to write random data to
the underlying disk device prior to creating the LUKS volume.  I believe I
referenced [0] on the Arch Linux wiki a bunch way back when, but you'll
find other great references on the Gentoo wiki as well.

cryptsetup is the utility you're looking for.  (As I'm sure you already
know...since your mailing list link mentions it.) :)

> Again, it depends on your use-case.
> --
> Digimer
> Papers and Projects: https://alteeve.ca/w/
> What if the cure for cancer is trapped in the mind of a person without
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[0] https://wiki.archlinux.org/index.php/Dm-crypt_with_LUKS

//  SilverTip257  //