[SATLUG] Personal RAID 6 array/ LED Monitor

travis+ml-satlug at subspacefield.org travis+ml-satlug at subspacefield.org
Mon Jul 5 16:58:39 CDT 2010


On Mon, Jul 05, 2010 at 02:33:36PM -0700, dondavis at reglue.org wrote:
> I've been thinking about getting a raid 6 array to save my personal data.
> I am considering a 3M card.

I'm using a 3Ware card - it works wonderfully, much more reliable than
software RAID.  I had one problem with it; on soft reboots sometimes
it doesn't reset properly.  But lately that hasn't been a problem,
and the fix was always a simple power-off and back on.

I use RAID 10.  Capacity is relatively cheap, and I believe that
mirroring gives best performance in terms of minimum I/Os per read and
write.   Could be wrong though, RAID 6 might be as good.  Check
storagemojo blog for details.

> What do you think about personal use of RAID 6? is it overkill? Should I
> just use RAID 0 and call it a day?

Don't do 0... you multiply your SPOFs by the number of drives.

...unless you're doing "poor man's RAID", where you rsync the data to
another location.  That has the nice effect of allowing you to fix an
accidental rm, in addition to giving you some recoverability due to
drive failure (you lose everything since last rsync, of course).

Of course, you don't need to use mirroring on backup filesystems.

I personally use RAID 10 for important data, and I do rsync backups
to a RAID 0 partition.  So in a way, I have two layers of redundancy.

Oh, and if you're interested in backing up your large capacity file
server, may I recommend hdb?

http://www.subspacefield.org/security/hdb/

It's working now, really fast (as fast as a a hard drive), simple
design, easy to understand, and secure.  What more could you want?

Of course, this is mostly for archival purposes.  If you're using
RAID 10 or 6 or even 5, you'll probably never need to recover your
primary filesystem.

> Additionally, I'd like to get a new mother board (ram and processor),
> case, and monitor to go with it. Suggestions?

Get a mobo that supports ECC RAM.  It's more expensive, and harder to
find, but I'm convinced it's a good idea - 4GB of RAM can have a
single bit error every day, on average, IIRC - can dig up references.
Since your file server will be caching all your disk data in RAM,
you want to protect that.

I'd personally get a 2 or more CPU box with dual cores in them, if you're
going to be doing disk crypto.  Here's my latest talk on disk crypto:

http://www.subspacefield.org/security/encrypted_storage_dc650_20100624/encrypted_storage_dc650_20100624.pdf

I did some timings, and if you're using it as a SMB/NFS file server
on GigE, you notice almost no degradation in performance from block
device crypto (e.g. cryptsetup).

> Does anyone have any experience with the LED (not LCD) monitors yet?

I have a large Samsung LED HDTV from Fry's, and it's awesome.  No
complaints whatsoever, works great as a monitor for my mythbuntu box
too.  Everyone raves about the brightness and clarity.  HDMI inputs
coming straight from an nVidia card.
-- 
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