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I am researching external HDD's capable or RAID 1 to store a large amount of video content during overseas filming. After filming, the content will be brought back to the office and offloaded onto our storage server.

After doing some research, I've found that I can buy an external drive with a built in RAID controller, or I can buy an external drive, with 2 HDD's, that I can configure in a RAID 1 array using the OS. RAID 1 is what we're looking for.

I've done some reading on software RAID vs. hardware RAID, but the resources I've found don't discuss performance as it relates to video content or what happens to a software RAID when the computer dies.

Question 1: Will the hardware RAID be more performant when dealing with large video files?

Question 2: If the mac dies, does my RAID die with it (will my data be accessible on another mac)?

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Question 1: Will the hardware RAID be more performant when dealing with large video files?

For some forms of RAID: Yes.
For RAID 1: No or negligible.

RAID 1 requires no complex calculations and modern CPU's are quite fast. There is not reason to go for hardware RAID just for two drives in RAID 1.

If you later want to add more drives or change to RAID 6 then the story changes.

For more information on how RAID (both HW and SW) works, check out this link. It explains the RAID level, potential performance gains and makes it clear what remains of your data if a disk dies.

Question 2: If the mac dies, does my RAID die with it (will my data be accessible on another mac)?

That depends on the form of RAID used:

  • HW RAID in the external drive (e.g. a Pegasus via Thunderbolt) will work fine on another computer.
  • Real software RAID should also just work. Possibly after installing drivers.
  • Fake HW RAID will need the same model motherboard/BIOS. But that is mostly a PC thing.

Software RAID usually writes its own information to the drives. If your motherboard or OS disk dies then you can still restore the RAID array on a different computer.


Just one warning: RAID is not backup.

RAID 1 will help if one drive fails. It will not help if the setup gets stolen, if lightning strikes etc etc.

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Isn't there significant performance improvement when reading? –  Daniel Beck Sep 20 '12 at 15:28
    
The improvement is seen where? Reading from a software RAID or a hardware RAID? –  James Hill Sep 20 '12 at 15:30
    
Both. Since both HW and SW RAID will be reading from multiple drives. Check this link which explains RAID in a very easy to understand way. serverfault.com/questions/339128/… –  Hennes Sep 20 '12 at 15:32
    
OK. From everything I'm reading - there seems to be no clear winner. What would be the safest form of RAID for our application - software or hardware (I understand RAID is not backup)? –  James Hill Sep 20 '12 at 15:35
    
As a follow up, one of my biggest concerns is this: If I use mac's built in capabilities for RAID, and the mac dies, do I lose the data on my RAID? If so, the single fault tolerance that RAID 1 provides isn't really there at all since the OS itself has a zero fault tolerance. –  James Hill Sep 20 '12 at 15:45
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