- Joined
- Mar 27, 2005
- Location
- Fresno, CA
- Thread Starter
- #21
Thank you for the super-clear instructions! . . . I'll probably refer back to that when I'm setting up the arrays. . .I think there are some semantics that need to be worked out. When I say RAID10 I'm referring to 4 drives (or 4 slices from 4 different drives) where they are grouped together into 2 pairs. Each pair is in RAID0 (for performance), and the 2 pairs are mirrored (for redundancy). RAID10 or RAID0+1 or RAID1+0 are the same thing as this afaik...someone correct me if I'm wrong here.
So, if you have 4x640GB Blacks...
Go into the Intel RAID BIOS (cntrl-I during boot) and first create a 560GB RAID0 array. Then create a RAID10 array w/ the remainder (2TB).
While installing the OS you can create all your partitions on the RAID0 array...make sure your first partition is OS for the best performance.
Concerning the RAID 0+1 versus RAID 1+0, I believe there is a difference. I put "raid 0+1 vs 1+0" in google, and found this article at the top:
http://www.pcguide.com/ref/hdd/perf/raid/levels/multXY-c.html
Here are the key statements about the topic. (The author uses an example of working with 10 disks):
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"RAID 0+1 = RAID 0, then RAID 1: Divide the ten disks into two sets of five. Turn each set into a RAID 0 array containing five disks, then mirror the two arrays. (Sometimes called a "mirror of stripes".)
RAID 1+0 = RAID 1, then RAID 0: Divide the ten disks into five sets of two. Turn each set into a RAID 1 array, then stripe across the five mirrored sets. (A "stripe of mirrors").
In many respects, there is no difference between them: there is no impact on drive requirements, capacity, storage efficiency, and importantly, not much impact on performance. The big difference comes into play when we look at fault tolerance.
RAID 0+1: We stripe together drives 1, 2, 3, 4 and 5 into RAID 0 stripe set "A", and drives 6, 7, 8, 9 and 10 into RAID 0 stripe set "B". We then mirror A and B using RAID 1. If one drive fails, say drive #2, then the entire stripe set "A" is lost, because RAID 0 has no redundancy; the RAID 0+1 array continues to chug along because the entire stripe set "B" is still functioning. However, at this point you are reduced to running what is in essence a straight RAID 0 array until drive #2 can be fixed. If in the meantime drive #9 goes down, you lose the entire array.
RAID 1+0: We mirror drives 1 and 2 to form RAID 1 mirror set "A"; 3 and 4 become "B"; 5 and 6 become "C"; 7 and 8 become "D"; and 9 and 10 become "E". We then do a RAID 0 stripe across sets A through E. If drive #2 fails now, only mirror set "A" is affected; it still has drive #1 so it is fine, and the RAID 1+0 array continues functioning. If while drive #2 is being replaced drive #9 fails, the array is fine, because drive #9 is in a different mirror pair from #2. Only two failures in the same mirror set will cause the array to fail, so in theory, five drives can fail--as long as they are all in different sets--and the array would still be fine."
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So I'm hoping that the Matrix controller does RAID 1+0 versus RAID 0+1. I suspect that it does RAID 1+0 because that is what is commonly referred to as "RAID 10" and I believe that some motherboards advertise it as "RAID 10."
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