[ale] raid suggestions

[mike at trausch.us]

On 02/09/2012 03:37 PM, Lightner, Jeff wrote:
> Hardware based (for true RAID) because it doesn't require CPU cycles.

Not only do today's CPUs run faster and process better than most RAID
controllers can or do, but there are at *least* a dozen reasons why the
use of hardware RAID is dubious at best.  Unless you're talking about a
one-off, terribly small deployment, software RAID is the way to go.

If necessary, have one system be the software RAID box and expose its
array over the network and have other systems be the consumers.

I use RAID 6 in one deployment, but I am looking to move away from that.
 That said, it has already saved my bacon in a situation where RAID 5
would have failed me (by a 10-second window!) and I would recommend it
if you don't have the money for more robust systems, but would urge
caution that the money really should be spent for the additional disks.
 Even at today's HDD prices.

There is a _single_ scenario where hardware RAID is a good idea (though
it's not for technical reasons):  if you have a vendor that you know
will be around, that you know will support their hardware for your
intended deployment lifecycle, and you know can be relied upon to
provide emergency support or accept liability for not having done so,
then go for it.  However, such a scenario is most likely to be
implemented simply because a PHB demands it, as opposed to technical
requirements meriting it.

	--- Mike

-- 
A man who reasons deliberately, manages it better after studying Logic
than he could before, if he is sincere about it and has common sense.
                                   --- Carveth Read, “Logic”

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