[mythtv-users] Better think twice before choosing an FS especially for LVM

Brandon Beattie brandon+myth at linuxis.us
Thu Sep 15 21:41:05 UTC 2005

On Thu, Sep 15, 2005 at 03:52:24PM -0500, Dan Littlejohn wrote:
> Another vote for RAID5 with XFS.  I stayed away from LVM so I could
> run XFS without worrying.  Used an old 600Mhz box and a hardware RAID
> controller, and mounted it with nfs.  Can replace the controller if it
> fails, replace a drive that fails, and expand the array on line.
> Maybe I am deluding myself because I do not understand all the details
> of LVM and the potential for XFS to corrupt, but I have been more than
> happy with this setup and it is in heavy usage.
> When they get on-line expansion working for adding devices (as I
> learned they are working on above) for software RAID, I think that
> would be my preference (most recoverable and cheapest).

... Just a few questions, for fun, and to get you to think. :)  Food for
thought and nothing is meant to criticize, just to make a few points.

What if you delete a file you needed by accident?  Or if the power
supply goes bad and fries the circuit boards on a two+ drives.  What 
raid controller is it too?  .. Are you sure you can still buy the same 
model, as you can't just swap an older 3ware raid card with a newer one 
and have it recognize the raid drives properly, and if the card goes out 
how much downtime will that be?  How much does a new raid card cost?  
What if the computer is stolen, the home floods, or burns?  Just how 
important is the data?  You may have a way around one of these problems, 
maybe a few of these, but how about every last possiblity, or where do 
you draw the line?  Can you admit that regardless of how complex your 
setup is, it's only as strong as its weakest link, and you likely don't 
know or won't admit that weakest link?  What exactly are you achieving 
by using raid5?  Does the phrase Raid5 make you feel invinsible?

I've had personal experience or direct relations with companies who've
faced every one of those problems above.  If reliablity is what you
want Raid5 alone is not a solution.  I personally think that there will
always be a good share of people who will want to use Raid5 (Maybe not
what they need though).  I also have a strong opinion that raid is
being sensationalized in use for Myth or any media center.  If you
disagree that's completely fine with me. :)  .. Let me know what you're
doing in a couple years though. 


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