[SGVLUG] Drive encryption and ReadyNAS expansion

[Claude Felizardo]

Any suggestions on encrypting drives or filesystems?  Don't need the drives
automounted at boot as these will be used for backups stored off-site.

In the past, I've been using mountloop which was a wrapper for losetup and
all that.  It was nice in that I just did something like this:

   mountloop AES encrypted-file mount-point
   ...
   umountloop mount-point

However it doesn't seem to work with the latest kernel.  Actually support
was dropped back in 2009 so I need to find something else.  What are people
using?


BTW, at last week's meeting I had asked if anyone was using a
Netgear/Infrant ReadyNAS and if they had any experience with replacing
drives to increase capacity.  I have a 4-bay model that came with two 500 GB
drives in a RAID-1 (mirror) configuration that I was able to expand a year
or two ago by adding a 3rd 500 GB.  I'm using their XRAID feature which
means it can automatically resize itself when you add drives or replace all
of the existing drives with larger drives.  So with 3x 500 GB drives I had
almost 900 GB of redundant space after OS overhead, etc.  So one of my
questions last week was rather than adding a 4th 500 GB drive and have it
auto-resize to 1.5 TB, should I upgrade the 3 existing drives now to say 1
TB ea for a total of 2 TB?  For those not familiar with RAID-5 the capacity
is (n-1) * size of smallest drive and you can lose 1 drive w/o losing data.

Over the weekend I saw that both Fry's and Best Buy had 2 TB Seagate 5400
drives on sale so I picked up one from each and opted to use one of my 1.5
TB backup drives for the 3rd.  I'm happy to report  that it worked even
though I inserted the 2 TB's first.  I didn't want to risk a hot swap so I
shut the box down, replaced one drive at a time and powered it up.  The box
recognized the new drive, sent out a series of emails at each step saying it
was initializing the drive, completed, started resync, and when the raid was
redundant.  After the 3rd swap and reboot, it said it found free space to
expand but I had to disable the snapshot first.  A few more reboots and it
now says it's 2.7 T with 1.9 T available.

I want to point out that I did not have to type any commands, no tweaking of
raid settings, nada.  Other than disabling the snapshot via the web gui, I
just swapped drives and cycled power.  Sure beats doing it by hand which
I've done too many times before.  This was an in-place rebuild.  And yes, I
have multiple backups of everything except for the last set of recordings
from my TiVo's.

Oh, as for why I got the drives from different places,  I had heard that you
should try to use drives from different batches, preferably different
manufactures, to reduce the risk of multiple drive failures before you can
replace the first one.   The serial numbers on the two Seagates looked
reasonably far apart though you really can't be sure.  I'll order a 3rd 2 TB
drive when I get a chance at which point my capacity will be close to 4 TB
which should be plenty for a few years yet.  :)

claude
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