[mythtv-users] RAID versus Drobo

Robin Hill myth at robinhill.me.uk
Sun Sep 9 19:12:22 UTC 2007


On Sun Sep 09, 2007 at 02:52:24PM -0400, Eric Robinson wrote:

> So what then is the difference between fake raid and software raid?
> 
There's essentially 3 different types of RAID setup:
 - Hardware RAID - this uses a dedicated processor to perform the RAID
                   calculations and each array will appear to the system
                   as a single drive.  A single data stream is therefore
                   sent and the controller splits it between the drives.
                   The actual implementation is specific to the
                   controller so arrays usually cannot be moved between
                   different controllers.
 - Software RAID - this uses the system processor to perform the RAID
                   calculations.  It's operating system specific and
                   maps the individual drives/partitions into an array.
                   It'll send separate data streams to each drive.
 - Firmware RAID - this also uses the system processor but is handled
                   via the motherboard/controller firmware.  Arrays can
                   be accessed from different operating systems
                   (providing they have driver support) but usually
                   cannot be moved between different motherboards.

Firmware RAID is also known as fake RAID because the motherboard
manufacturers make claims equating it with true hardware RAID whereas it
actually has a lot more in common with software RAID.

HTH,
        Robin

-- 
     ___        
    ( ' }     |       Robin Hill        <myth at robinhill.me.uk>  |
   / / )      | Little Jim says ....                            |
  // !!       |      "He fallen in de water !!"                 |
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