hw vs sw raid (was Re: [TriLUG] RAID newbie question...)

[Mike Johnson]

Jason Tower [jason at cerient.net] wrote:
 
> true story: last year i was called in to fix a system that used software 
> raid 1 on a data partition (but not the other partitions).  one of the 
> disks had failed and the system would no longer boot.  i slapped a 
> knoppix cd in the drive, brought it up, mounted the remaining raid 
> partition, and scp'd the data to another system.  software raid 1 is a 
> good thing :-)

This is an important point, that perhaps may have been missed.  With HW
RAID, you're pretty much locked in.  If you HW RAID card dies (it
sucks), you either swap in the spare that you had laying around, hope
you can find a used one off eBay, or just kiss your data good-bye and
head for the tapes.  There is no 'standard' for HW RAID data.  Every
vendor (and oftentimes even within a vendor -- different products) has a
different format for how they store their blocks.  For instance, if you
have a HW RAID set up with 3Ware, you cannot use one of the Promise
(yes, they make a -true- HW IDE RAID card) if the 3Ware dies.

If you're using software RAID, you can move the drives around and still
access them, or, as Jason did, even use knoppix.

So, if you're looking for cheap, decent perfomance, just go software
RAID.  There is a performance hit, but the cost and flexibility make up
for it.

Mike
-- 
"If life hands you lemons, YOU BLOW THOSE LEMONS TO BITS WITH 
 YOUR LASER CANNONS!" -- Brak

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