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What is the difference between hardware raid 0+1 and 2 or more RAID 0 with disk span? what are the differences: advantages and disadvantages?

user2119955
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  • Performance, supportability, your sanity. Also, you probably want to use hardware 1+0, not 0+1. Why would you ever want to introduce software RAID into the mix if you have a controller that can natively handle the RAID level that you want? – MDMarra Mar 06 '13 at 14:26
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    i don't think a such important question should have a rating of -2. The link you provided don't talk about os-raid vantage disantage – user2119955 Mar 06 '13 at 14:52
  • @user2119955 I agree that this question isn't a duplicate of the question you were linked to. But I also don't think that this is `"such an important question"`. Can you explain why you're even considering software RAID on top of hardware RAID? – MDMarra Mar 06 '13 at 14:55
  • I discovered that os can allow software raid only last week, disk usage is growing up very fast so i've to plan a storage strategy, and want to know the vantage/disadvantage of a software solution over hw in order to make a decision – user2119955 Mar 06 '13 at 15:03

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First of all, you'd want to do 1+0, not 0+1. 1+0 is more fault tolerant, has shorter rebuild times, and almost identical performance. There's a reason you never see 0+1 in production and 1+0 is everywhere.

Second of all, why would you want to bring software RAID into the mix? It's generally accepted that a good hardware controller is superior to most forms of software RAID (ZFS aside). If you do have a reason for software RAID over hardware RAID though,like disk portability, then why are you using hardware RAID at all. Mixing both gives you the benefit of neither.

Also, imagine this support call:

You: My disk arrays keep degrading.

Dell: OK, let's take a look at the PERC here...Ok so it looks healthy, but you're using software RAID on top. This is most likely a Microsoft issue.

Microsoft: Sorry, this isn't our problem, it's the RAID controller underneath causing the software RAID to degrade.

Why would you ever want to put yourself in that situation without having a very good reason?

MDMarra
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  • I discovered that os can allow software raid only last week, disk usage is growing up very fast so i've to plan a storage strategy, and want to know the vantage/disadvantage of a software solution over hw in order to make a decision – user2119955 Mar 06 '13 at 15:04
  • @user2119955 that's not the question that you asked at all. What you asked was about combining hardware RAID with software RAID on a single volume. That's different than "What advantages to hardware RAID and software RAID have over each other" which **is** covered in the question that you were linked to – MDMarra Mar 06 '13 at 15:12
  • http://www.cyberciti.biz/tips/raid-hardware-vs-raid-software.html – user2119955 Mar 06 '13 at 15:31